C Programs

BinarySearch.c

#include <stdio.h>

void main(){
    int A[50],i,low,mid,high,n,key;
    printf("Enter number of elements");
    scanf("%d",&n);
    
    printf("Enter elements in array");
    for (i=0;i<n;i++){
   	 scanf("%d",&A[i]);
    }
    printf("Enter value to find");
    scanf("%d",&key);
	low = 0;                     
    high = n-1;                  
	mid = (low+high)/2;          
    while (low<=high){           
    	mid = (low+high)/2;      
   	 if (A[mid] < key){          
   			 low=mid+1;          
   		}
   	 else if(A[mid]==key){       
            	printf("Element found!");
   			 break;    
    	}
    else{                       
            	high = mid-1;   
   		}                         
   	 
    if (low>high){              
        printf("Not found");
    }
     }
}

CircularQueue.c

#include <stdio.h>

#define MAX 3

int queue[MAX];
int front = -1;
int rear = -1;


void enqueue(int element){

    if (front == -1 && rear == -1){
   	 front = 0;  
   	 rear = 0;
   	 queue[rear] = element;  
   	 }
    else if((rear+1)%MAX == front){   
   	 printf("\nQueue overflow\n");
   	 }
    else{
   	 rear = (rear+1)%MAX;                 
   	 queue[rear] = element;          
    
    }
}

int dequeue(){
    if (front == -1 && rear == -1){
   	 printf("\nQueue underflow\n");
    }
    else if(front == rear){      
   	 printf("The dequeued element is %d",queue[front]);
   	 front = -1;
   	 rear = -1;
    }
    else{
    printf("\n The dequeued element is %d",queue[front]);
    front = (front+1)%MAX;   
    }
}

int display(){
    int i = front;
    if (front == -1 && rear ==-1){  
   	 printf("\nQueue is empty\n");
   	 }
    else if((rear+1)%MAX == front){    
   	 i = 0;
   	 while(i<MAX){
   		 printf("\n%d",queue[i]);
   		 i = i+1;
   	 }
    }
    else{
   	 printf("\n===========================\n");
   	 printf("Elements in the queue are");
   	 while(i<=rear){
   		 printf("\n%d",queue[i]);
   		 i = (i+1)%(MAX+front);    
   	 }
   	 printf("\n===========================\n");
    }
}


void main(){
    int choice = 1,x;
    while(choice < 4 && choice!=0){
   	 printf("\n===========================\n");
   	 printf("1.Insert into queue\n");
   	 printf("2.Delete from queue\n");
   	 printf("3.Display from queue\n");
   	 printf("4.Exit\n");
   	 printf("\n===========================\n");
   	 printf("Enter your choice");
   	 
   	 scanf("%d",&choice);
   	 switch(choice){
   		 case 1 : printf("Enter the element to be inserted");
   			 scanf("%d",&x);
   			 enqueue(x);
   			 break;
   		 case 2 : dequeue();
   			 break;
   		 case 3 : display();
   			 break;
   	 }
    }
}

Dequeue.c

#include <stdio.h>

#define MAX 10

int queue[MAX];
int front = -1, rear = -1;
void insert_rearend();
void insert_frontend();
void delete_rearend();
void delete_frontend();
void display();

void main(){
    int choice;
    do{
   	 printf("\n--------------------\n");
   	 printf("\n1.Insert at rear end\n");
   	 printf("\n2.Insert at front end\n");
   	 printf("\n3.Delete at rear end\n");
   	 printf("\n4.Delete at front end\n");
   	 printf("\n5.Display\n");
   	 printf("\n6.Exit\n");
   	 
   	 printf("Enter your choice");
   	 scanf("%d",&choice);
   	 
   	 switch(choice){
   		 case 1: insert_rearend();
   			 break;
   		 case 2: insert_frontend();
   			 break;
   		 case 3: delete_rearend();
   			 break;
   		 case 4: delete_frontend();
   			 break;
   		 case 5: display();
   			 break;
   	 }
    }while (choice!=6);
}



void insert_rearend(){
    int val;
    printf("Enter value to be added");
    scanf("%d",&val);   
    if ((front == 0 && rear == MAX-1) || (front == rear+1))  
   	 printf("OverFlow");
    if (front == -1){
   	 front = 0;  
   	 rear = 0;
    }
    else{
   	 if (rear == MAX-1) 
   		 rear = 0;      
   	 else
   		 rear = rear+1; 
    }
    queue[rear] = val;  

}

void insert_frontend(){

    int val;
    printf("Enter value to be added");
    scanf("%d",&val);
    if ((front == 0 && rear == MAX-1) || (front == rear+1))
   	 printf("OverFlow");
    if (front == -1){
   	 front = 0;
   	 rear = 0;
    }
    else{
   	 if (front == 0)     
   		 front = MAX-1;  
   	 else
   		 front = front -1; 
    }
    queue[front] = val;   
}

void delete_rearend(){
    if(front == -1){   
   	 printf("Underflow");
   	 return;
    }
    printf("Deleted Element is %d\n",queue[rear]);
    if (front ==rear){
   	 front = -1;  
   	 rear = -1;
    }
    else{
   	 rear = rear -1;   
    }
}

void delete_frontend(){
    if(front == -1){
   	 printf("Underflow");
   	 return;
    }
    printf("Deleted Element is %d\n",queue[front]);
    if (front ==rear){
   	 front = -1;
   	 rear = -1;
    }
    else{
   	 if (front == MAX -1)
   		 front = 0;
   	 else
   		 front = front+1;  
    }
}

void display(){
    if (front == -1){
   	 printf("\n queue is empty\n");
   	 return;
    }
    printf("\n The elements in queue are...\n");
    if(front <=rear){
   	 int tempFront = front;
   	 while(tempFront<=rear){
   		 printf("%d\t",queue[tempFront]);
   		 tempFront++;
   	 }
    }
    else{
   	 int tempFront = front;
   	 while(tempFront<=MAX-1){      
   		 printf("%d\t",queue[tempFront]);
   		 tempFront++;
   	 }
   	 tempFront = 0;
   	 while(tempFront<=rear){      
   		 printf("%d\t",queue[tempFront]);
   		 tempFront++;
   	 }
    }
    printf("\n");
}

LinearSearch.c

#include <stdio.h>

void main(){
    int A[50],len,i,j,key,flag=0;
    printf("Enter length of the array");
    scanf("%d",&len);
    
    printf("Enter elements in the array");
    for (i=0;i<len;i++){
   	 scanf("%d",&A[i]);
    }
    
    printf("Enter the element to be searched");
    scanf("%d",&key);
    for (i=0;i<len;i++){
   	 if (A[i]==key){
   		 flag=1;
   		 break;    
   	 }
    }
    if (flag==1){
   	 printf("Element found!");
    }
    else{
   	 printf("Element not found");
    }
}

Polynomials.c

#include <stdio.h>

void main(){
    int A[50][50],B[50],i,j;
    int polyno,polydegree;
    int maxpolydegree;
    printf("Enter number of polynomials\n");
    scanf("%d",&polyno);
    
    for(i=0;i<polyno;i++){
   	 printf("Enter Polynomial no %d\n",i+1);
   	 printf("Enter the degree of the polynomial\n");
   	 scanf("%d",&polydegree);
   	 if (polydegree>maxpolydegree)
   		 maxpolydegree = polydegree;
   	 for(j=0;j<=polydegree;j++){
   		 if (j==0){
   			 printf("Enter the constant\n");
   			 scanf("%d",&A[i][j]);}
   		 else{
   			 printf("Enter the coefficient of x^%d\n",j);
   			 scanf("%d",&A[i][j]);    
   		 }
   	 
   	 }
   	 
    }
    
    printf("Given polynomial data");
    for(i=0;i<polyno;i++){
   	 printf("\n");
   	 for(j=0;j<=maxpolydegree;j++){
   		 printf("%d \t",A[i][j]);

   	 
   	 }
   	 
    }
    
    for(i=0;i<=maxpolydegree;i++){
   	 for(j=0;j<=polyno;j++){
   		 B[i] += A[j][i];
   	 }    
    }
    
    printf("\nSum of the polynomials\n");
    
    for(i=maxpolydegree;i>=0;i--){
   	 if (i==0)
   		 printf("%d \t",B[i]);
   	 else
   		 printf("%d x^%d + ",B[i],i);
    
    }
    printf("\n");
    
    
    

}

PriorityQueue.c




#include<stdio.h>
#include<limits.h>
#define MAX 100
int idx = -1;
int pqVal[MAX];
int pqPriority[MAX];
int isEmpty()
{
    return idx == -1;
}
int isFull()
{
    return idx == MAX - 1;
}
void enqueue(int data, int priority)
{
    if(!isFull()){
        idx++;
        pqVal[idx] = data;             
        pqPriority[idx] = priority;
    }
}

int peek()
{
    int maxPriority = INT_MIN; 
    int indexPos = -1;
    for (int i = 0; i <= idx; i++)
    {
        if (maxPriority == pqPriority[i] && indexPos > -1 && pqVal[indexPos] < pqVal[i]){
            maxPriority = pqPriority[i];
            indexPos = i;
        }
        else if (maxPriority < pqPriority[i])  
                                               
        {
            maxPriority = pqPriority[i];      
            indexPos = i;     
        }
    }
    return indexPos;  
}

void dequeue()
{
    if(!isEmpty()){
        int indexPos = peek();   
        for (int i = indexPos; i < idx; i++){  
            pqVal[i] = pqVal[i + 1];           
            pqPriority[i] = pqPriority[i + 1];
        }
        idx--; 
    }
}

void display()
{
    for (int i = 0; i <= idx; i++)
        {
        printf("(%d, %d)\n",pqVal[i], pqPriority[i]);
        }
}
void main()
{
    int x,y,ch;
    do
    {
        printf("\t==== Menu ====\n");
        printf("\t 1. Enqueue\n");
        printf("\t 2. Dequeue\n");
        printf("\t 3. Display\n");
        printf("\t 0. Exit\n");
        printf("Your Choice :- \t");
        scanf("%d",&ch);
        switch(ch){
            case 1:
                printf("Enter value, its priority :- \n");
                scanf("%d%d",&x,&y);
                enqueue(x,y);
                break;
            case 2:
                dequeue();
                break;
            case 3:
                display();
                break;
            case 0:
                break;
            default:
                printf("Invalid Choice .....\n");
        }
    } while(ch != 0);
}

Queue.c

#include <stdio.h>
#include <stdlib.h>
#define MAX 5


int queue_array[MAX];

int rear = -1;
int front = -1;

void insert(){
    int item;
    if(rear == MAX-1)
   	 printf("\nQueue Overflow\n");
    else{
   	 if(front == -1)
   		 front = 0;  
   	 printf("\nInsert element in queue\n");
   	 scanf("%d",&item);
   	 rear = rear + 1;
   	 queue_array[rear] = item;   
    }
}

void delete(){
    if(front == -1 || front > rear){    
   	 printf("\nQueue underflow\n");
    }
    else{
   	 printf("\nElement deleted from queue is %d",queue_array[front]);
   	 front = front + 1;      
    }
}

void display(){
    int i;
    if (front == -1){
   	 printf("\nQueue is empty\n");
    }
    else{
   	 printf("\nQueue is..\n");
   	 for(i=front;i<=rear;i++){       
   		 printf("%d",queue_array[i]);
   		 printf("\n");
   	 
   	 }
    
    }


}
int main(){
    int choice;
    while(1){
   	 printf("\n1.Insert\n2.Delete\n3.Display\n4.Quit");
   	 printf("\nEnter your choice");
   	 scanf("%d",&choice);
   	 switch(choice){
   		 case 1:insert();
   			 break;
   		 case 2:delete();
   			 break;
   		 case 3:display();
   			 break;
   		 case 4:exit(0);
   			 break;
   	 
   	 }
    
    
    }
    
}

SparseMatrix.c

#include <stdio.h>

void main(){
	int a[50][50],n,m,i,j,count=0,k=0,b[3][20],countn=0;
	printf("Enter the no of row and columns");
	scanf("%d%d",&n,&m);
	printf("Enter elements in matrix");
	for(i=0;i<n;i++){
    	for(j=0;j<m;j++){
        	scanf("%d",&a[i][j]);
    	}
	}
	for(i=0;i<n;i++){
    	for(j=0;j<m;j++){
        	if(a[i][j]==0)
            	count = count+1;
        	else
            	countn++;
    	}
	}

	for(i=0;i<n;i++){
    	printf("\n");
    	for(j=0;j<m;j++){
        	printf("%d \t",a[i][j]);
    	}
	}

	if (count>(m*n)/2){
    		printf("\n Its a sparse matrix");
	}
	else{
    		printf("\n Its not a sparse matrix");
	}
	while(k!=countn){
    	for(i=0;i<3;i++){
        	for(j=0;j<m;j++){
            	if(a[i][j]!=0){
                	k++;
                	b[0][k-1]=i;
                	b[1][k-1]=j;
                	b[2][k-1] = a[i][j];
               	 
            	}
        	}
    	}
   	 
	}

	for(i=0;i<3;i++){
    	printf("\n");
    	for(j=0;j<countn;j++){
        	printf("%d\t",b[i][j]);
    	}
	}
}

Stack.c

#include <stdio.h>
#include <stdlib.h>
#define size 4

int top=-1,array[size];

void push(){
    int x;
    if (top==size-1)
   	 printf("\n Overflow!\n");
    else{
   	 printf("\n Enter element to be inserted to stack");
   	 scanf("%d",&x);
   	 top=top+1;
   	 array[top] = x;
    }
}

void pop(){
    if (top == -1)
   	 printf("\nUnderflow\n");
    else{
   	 printf("Popped element %d",array[top]);
   	 top = top-1;
    
    }
}

void show(){
    if (top == -1)
   	 printf("\nUnderflow\n");
    else{
   	 printf("\n Elements present in stack \n");
   	 for(int i=top;i>=0;--i)
   		 printf("%d \n",array[i]);
    
    }

}

void main(){
    int choice;
    while(1){
   	 printf("Operations performed by stack\n");
   	 printf("1.Push\n2.Pop\n3.Show\n4.End");
   	 printf("Enter the choice");
   	 scanf("%d",&choice);
   	 switch(choice){
   		 case 1:push();
   			 break;
   		 case 2:pop();
   			 break;
   		 case 3:show();
   			 break;
   		 case 4:exit(0);
   	 
   	 
   	 }
    }
}

binarytreelinkedlist.c

#include<stdio.h>
#include<stdlib.h>
typedef struct bin
    {
    int data;
    struct bin *left;
    struct bin *right;
} node;

void insert(node *, node *);
void inorder(node *);
void preorder(node *);
void postorder(node *);
int height(node *root);
void getLastNodeAndItsParent(node *root, int level, node *parent);
void deleteNode(node *root);
node *get_node();
node *lastNode, *parentOfLastNode;

void main()
{
    int choice;
    char ans = 'n';
    node *new, *root;
    root = NULL;
    do{
        printf("\n\t==== MENU ====\n");
        printf("\t 1. Create\n");
        printf("\t 2. Inorder\n");
        printf("\t 3. Pre-order\n");
        printf("\t 4. Post-Order\n");
        printf("\t 5. Delete A Node\n");
        printf("\t 6. Exit\n");
        printf("\nYour Choice :- \t");
        scanf("%d",&choice);
        switch(choice)
        {
            case 1:
                new = get_node();
                printf("\t Enter the element :- \t");
                scanf("%d",&new->data);
                if(root == NULL)
                    root = new;
                else
                    insert(root,new);
                break;
            case 2:
                if(root == NULL)
                    printf("Tree is not created, It is empty.\n");
                else
                    inorder(root);
                break;
            case 3:
                if(root == NULL)
                    printf("Tree is not created, It is empty.\n");
                else
                    preorder(root);
                break;
            case 4:
                if(root == NULL)
                    printf("Tree is not created, It is empty.\n");
                else
                    postorder(root);
                break;
            case 5:
                if(root == NULL)
                    printf("Tree is Empty, Cannot perform Deletion..\n");
                else
                    deleteNode(root);
                break;
            case 6:
                break;
            default:
                printf("Invalid Choice....\n");
        }
    }
    while(choice != 6);
}

node *get_node(){
        node *temp;
        temp = (node*) malloc(sizeof(node));
        temp->left = NULL;
        temp->right = NULL;
        return temp;
}

int height(node *root){
    int maximum, lheight, rheight;
    if (root == NULL)
    return 0;
    lheight = height(root->left) + 1;
    rheight = height(root->right) + 1;
    maximum = (lheight>rheight)?lheight:rheight;
    return maximum;
}

void getLastNodeAndItsParent(node *root, int level, node *parent)
{
    if (root == NULL)
        return;
    if (level == 1){
            lastNode = root;
            parentOfLastNode = parent;
    }
    getLastNodeAndItsParent(root->left, level - 1, root);
    getLastNodeAndItsParent(root->right, level - 1, root);
}
void insert(node *root, node *new){
    int ch;
    printf("\t Where to insert left/right of %d ? (L - 1/R - 2) :- \t",root->data);
    scanf("%d",&ch);
    if(ch == 2){
        if(root->right == NULL){
            root->right = new;
        }
        else{
            insert(root->right, new);
        }
    }
    else{
        if(root->left == NULL){
            root->left = new;
        }
        else{
            insert(root->left, new);
        }
    }
}

void deleteNode(node *root){
    int levelOfLastNode = height(root);
    getLastNodeAndItsParent(root, levelOfLastNode, NULL);
    if (lastNode && parentOfLastNode){
        if (parentOfLastNode->right){
            printf("Deleted Node is %d\n",(parentOfLastNode->right)->data);
            parentOfLastNode->right = NULL;
        }
        else{
            printf("Deleted Node is %d\n",(parentOfLastNode->left)->data);
            parentOfLastNode->left = NULL;
        }
    }
    else
    printf("\tEmpty Tree..\n");
}

void inorder(node *temp)
{
    if(temp != NULL){
        inorder(temp->left);
        printf("%d\t",temp->data);
        inorder(temp->right);
    }
}
void preorder(node *temp)
{
    if(temp != NULL){
        printf("%d\t",temp->data);
        inorder(temp->left);
        inorder(temp->right);
    }
}
void postorder(node *temp)
{
    if(temp != NULL){
        inorder(temp->left);
        inorder(temp->right);
        printf("%d\t",temp->data);
    }
}

infixtopostfixandeval.c

#define SIZE 50
#include <ctype.h>
#include <stdio.h>
#include <math.h>
char s[SIZE];
int top = -1;

void push(char elem){
        s[++top] = elem;
}
char pop(){
    return (s[top--]);
}
int priority(char elem)
    {
        switch (elem)
        {
        case '#':
        return 0;
        case '(':
        return 1;
        case '+':
        case '-':
        return 2;
        case '*':
        case '/':
        return 3;
        }
    }
void infix_to_postfix(char infix[], char postfix[]){
    char ch, elem;
    int i = 0, k = 0;
    push('#');                  
    while ((ch = infix[i++]) != '\n'){
        if (ch == '(')          
            push(ch);
        else if (isalnum(ch))   
            postfix[k++] = ch;
        else if (ch == ')'){    
            while (s[top] != '(')  
                postfix[k++] = pop();
            elem = pop();
        }
        else{ 
            while (priority(s[top]) >= priority(ch))  
                postfix[k++] = pop();
            push(ch);                                 
        }
    }
    while (s[top] != '#')                             
        postfix[k++] = pop();
    postfix[k] = 0;                                   
    }
    int eval_postfix(char *postfix)
    {
        char ch;
        int i = 0, op1, op2;
        while((ch = postfix[i++]) != 0)               
        {
            if(isdigit(ch))                           
                push(ch-'0');                         
            else
                {
                    op2 = pop();                      
                    op1 = pop();
                    switch(ch)
                    {
                    case '+' :
                        push(op1+op2);
                        break;
                    case '-' :
                        push(op1-op2);
                        break;
                    case '*' :
                        push(op1*op2);
                        break;
                    case '/' :
                        push(op1/op2);
                        break;
                    case '^':
                        push(pow(op1,op2));
                        break;
                    }
                }
        }
        return s[top];
}

char infx[50], pofx[50];
void main()
{
    printf("\nInput the infix expression: ");
    fgets(infx, 50, stdin);
    infix_to_postfix(infx, pofx);
    printf("\nGiven Infix Expression: %sPostfix Expression: %s", infx, pofx);
    top = -1;
    printf("\nResult of evaluation of postfix expression : %d\n", eval_postfix(pofx));
}

polynomialAddnMult.c

#include <stdio.h>
#include <stdlib.h>
struct poly{
    int coefficient;
    int exponential;
    struct poly *ptr;
};

struct poly *p =NULL,*q=NULL,*r=NULL;

struct poly *pptr,*qptr;

struct poly *add(struct poly *header,int coeff,int expo){
    struct poly *newnode,*temp=header;
    newnode = (struct poly*)malloc(sizeof(struct poly));
    newnode->coefficient = coeff;
    newnode->exponential = expo;
    newnode->ptr = NULL;
    
    if (header==NULL){
   	 header = newnode;
    }
    else{
   	 while(temp->ptr!=NULL){
   		 temp = temp -> ptr;
   	 }
    temp -> ptr = newnode;
    return header;
    }
}
void display(struct poly *header){
    struct poly *current = header;
    if(header==NULL)
   	 printf("list is empty");
    else{
   	 while(current!=NULL){
   		 if(current->ptr!=NULL){
   			 printf(" %d x^%d +",current->coefficient,current->exponential);
   		 }
   		 else{
   			 printf(" %d x^%d",current->coefficient,current->exponential);
   		 }
   		 current = current->ptr;
   	 }
    }
}

void addition(struct poly *p,struct poly *q){
    int result;
    pptr= p,qptr = q;
    if(pptr==NULL){
   	 printf("pptr is null");
    }
    while((pptr!=NULL)&&(qptr!=NULL)){
   	 if (pptr->exponential > qptr->exponential){
   		 printf("abc");
   		 r = add(r,pptr->coefficient,pptr->exponential);
   		 pptr = pptr -> ptr;
   		 
   	 }
   	 else if(pptr->exponential < qptr->exponential){
   		 printf("abc");
   		 r = add(r,qptr->coefficient,qptr->exponential);
   		 qptr = qptr->ptr;
   	 }
   	 else{
   		 result = qptr->coefficient,qptr->coefficient;
   		 r= add(r,pptr->coefficient+qptr->coefficient,pptr -> exponential);
   		 qptr = qptr->ptr;
   		 pptr = pptr->ptr;
   	 }
    }
    while(pptr!=NULL){
   	 r=add(r,pptr->coefficient,pptr->exponential);
   	 pptr = pptr->ptr;
    }
    while(qptr!=NULL){
   	 r=add(r,qptr->coefficient,qptr -> exponential);
   	 
   	 qptr = qptr->ptr;
    }
    
}
    
struct poly *sort_add(struct poly *header,int coeff,int expo){
   	 
   	 struct poly *next = header,*prev = NULL;
   	 struct poly *newnode;
   	 newnode = (struct poly *) malloc(sizeof(struct poly*));
   	 newnode -> coefficient = coeff;
   	 newnode -> exponential = expo;
   	 newnode -> ptr=NULL;
   	 if(header == NULL){
   		 header = newnode;
   	 }
   	 else{
   		 while(next!=NULL && next -> exponential > expo){
   			 prev = next;
   			 next = next ->ptr;
   		 }
   		 if(prev == NULL){
   			 if (next ->exponential ==expo){
   				 next -> coefficient = coeff+ next->coefficient;
   				 free(newnode);
   			 }
   			 else{
   				 newnode -> ptr = next;
   				 header = newnode;
   			 }
   		 }
   		 else{
   			 if((next!=NULL) && (next ->exponential ==expo)){
   				 next -> coefficient = next -> coefficient +coeff;
   				 free(newnode);
   			 }
   			 else{
   				 prev -> ptr = newnode;
   				 newnode -> ptr = next;
   			 
   			 }
   			 
   		 }
   		 return header;
   	 }
   	 
    }
void multiplication(struct poly *p,struct poly *q){
   	 int coeff,expo;
   	 pptr=p;
   	 qptr = q;
   	 while(pptr!=NULL){
   		 qptr = q;
   		 while(qptr!=NULL){
   			 coeff = pptr->coefficient * qptr->coefficient;
   			 expo = pptr->exponential + qptr->exponential;
   			 r= sort_add(r,coeff,expo);
   			 qptr = qptr -> ptr;
   		 }
   		 pptr = pptr->ptr;
   	 }
   	 
}
    
    
void main(){
    int a,n,coeff,expo;
    //printf("polynomial representation");
    printf("Enter number of elements in 1st polynomial");
    scanf("%d",&n);
    
    for(int i=0;i<n;i++){
   	 printf("Enter coefficient ");
   	 scanf("%d",&coeff);
   	 printf("Enter exponential ");
   	 scanf("%d",&expo);
   	 p = add(p,coeff,expo);
   	 printf("\n");
    }
    printf("Enter no of elements in 2nd polynomial");
    scanf("%d",&n);
    for(int i=0;i<n;i++){
   	 printf("Enter the coefficient");
   	 scanf("%d",&coeff);
   	 printf("Enter exponential");
   	 scanf("%d",&expo);
   	 q = add(q,coeff,expo);
   	 printf("\n");
    }
    printf("Polynomial 1 is ");
    display(p);
    printf("\n");
    printf("Polynomial 2 is ");
    display(q);
    printf("\n 1.Addition \n 2. Multiplication ");
    scanf("%d",&a);
    switch(a){
    case 1: addition(p,q);
    	printf("The result is");
    	display(r);
   	 break;
    case 2: multiplication(p,q);
    	printf("The result is");
    	display(r);
   	 break;
    default: printf("Invalid Choice");
   	 break;
    }
    
}

singlylinkedlist.c

#include<stdlib.h>
#include<stdio.h>
void display();
void insert_begin();
void insert_end();
void insert_pos();
void delete_begin();
void delete_end();
void delete_pos();

struct node{
    int info;
    struct node *next;

};

struct node *start = NULL;

int main(){
    int choice;
	printf("\n Menu \n");
	printf("\n1.Display");
	printf("\n2.Insert at the beginning");
	printf("\n3.Insert at the end");
	printf("\n4.Insert at specified position");
	printf("\n5.Delete from beginning");
	printf("\n6.Delete from the end");
	printf("\n7.Delete from specific position");
	printf("\n8.Exit");
    while(1){
   	 printf("\n Enter your choice");
   	 scanf("%d",&choice);
   	 switch(choice){
   		 case 1: display();
   			 break;
   		 case 2: insert_begin();
   			 break;
   		 case 3: insert_end();
   			 break;
   		 case 4: insert_pos();
   			 break;
   		 case 5: delete_begin();
   			 break;
   		 case 6: delete_end();
   			 break;
   		 case 7: delete_pos();
   			 break;
   		 case 8: exit(0);
   			 break;
   		 default: printf("\n Wrong choice");
   	 }
   		 
    
    }
    return 0;

}

void display(){
    struct node *ptr;
    if(start==NULL){
   	 printf("\n List is empty");
   	 return;
    }
    else{
   	 ptr=start;
   	 printf("In the list elements are\n");
   	 while(ptr!=NULL){
   		 printf("%d\t",ptr->info);
   		 ptr=ptr->next;
   	 }
    }
}

void insert_begin(){
    struct node *temp;
    temp = (struct node*)malloc(sizeof(struct node));
    if(temp==NULL){
   	 printf("\n Overflow");
   	 return;
    }
    
    printf("\n Enter the data value of the node \t");
    scanf("%d",&temp->info);
    temp->next = NULL;
    if(start==NULL)
   	 start = temp;
    else{
   	 temp->next=start;
   	 start = temp;
    }
}

void insert_end(){
    struct node *temp,*ptr;
    temp = (struct node*)malloc(sizeof(struct node));
    
    if(temp==NULL){
   	 printf("\n Overflow");
   	 return;
    }
    
    printf("\n Enter the data value of the node \t");
    scanf("%d",&temp->info);
    temp->next = NULL;
    if(start==NULL)
   	 start = temp;
    else{
   	 ptr=start;
   	 while(ptr->next!=NULL){
   		 ptr=ptr->next;   	 
   	 }
   	 ptr->next = temp;
    }
}

void insert_pos(){
    struct node *ptr,*temp;
    int i,pos;
    temp = (struct node*)malloc(sizeof(struct node));
    
    if(temp==NULL){
   	 printf("\n Overflow");
   	 return;
    }
    
    printf("\n Enter the position for the new node to be inserted \t");
    scanf("%d",&pos);
    printf("\n Enter the data value of the node \t");
    scanf("%d",&temp->info);
    temp->next = NULL;
    
    if(pos==0){
   	 temp->next=start;
   	 start = temp;
    }
    else{
   	 for(i=0,ptr=start;i<pos-1;i++){
   		 ptr = ptr->next;
   		 if(ptr==NULL){
   			 printf("\n Position not found");
   			 return;
   		 }
   	 }
   	 temp->next = ptr->next;
   	 ptr->next = temp;
    }
}


void delete_begin(){
    struct node *ptr;
    if(start==NULL){
   	 printf("\n Underflow");
   	 return;
    }
    else{
   	 printf("1");
   	 ptr=start;
   	 printf("2");
   	 start = start->next;
   	 printf("\n The deleted element is %d \t",ptr->info);
   	 free(ptr);
    }

}

void delete_end(){
    struct node *temp, *ptr;
    if(start==NULL){
   	 printf("\n Underflow");
   	 return;
    }
    else if(start->next==NULL){
   	 ptr=start;
   	 start=NULL;
   	 printf("\n The deleted element is %d",ptr->info);
   	 free(ptr);
    }
    else{
   	 ptr=start;
   	 while(ptr->next!=NULL){
   		 temp = ptr;
   		 ptr=ptr->next;
   	 }
   	 temp->next = NULL;
   	 printf("\n The deleted element is %d \t",ptr->info);
   	 free(ptr);
    }
}

void delete_pos(){
    int i,pos;
    struct node *ptr, *temp;
    if(start==NULL){
   	 printf("\n Underflow");
   	 exit(0);
    }
    else{
   	 printf("\n Enter the position to be deleted");
   	 scanf("%d",&pos);
   	 if(pos == 0){
   		 ptr = start;
   		 start = start->next;
   		 printf("\n The deleted element is %d \t",ptr->info);
   		 free(ptr);
   	 }
   	 else{
   		 ptr = start;
   		 for(i=0;i<pos;i++){
   			 temp = ptr;
   			 ptr = ptr->next;
   			 if(ptr == NULL){
   				 printf("\n Position not found");
   				 return;
   			 }
   		 
   		 }
   		 temp->next = ptr->next;
   		 printf("\n The deleted element is %d \t",ptr->info);
   		 free(ptr);
   	 }
    
    }
}

Sorting Programs

BinarySearch.c

#include <stdio.h>

void main(){
    int A[50],i,low,mid,high,n,key;
    printf("Enter number of elements");
    scanf("%d",&n);
    
    printf("Enter elements in array");
    for (i=0;i<n;i++){
   	 scanf("%d",&A[i]);
    }
    printf("Enter value to find");
    scanf("%d",&key);
	low = 0;                     
    high = n-1;                  
	mid = (low+high)/2;          
    while (low<=high){           
    	mid = (low+high)/2;      
   	 if (A[mid] < key){          
   			 low=mid+1;          
   		}
   	 else if(A[mid]==key){       
            	printf("Element found!");
   			 break;    
    	}
    else{                       
            	high = mid-1;   
   		}                         
   	 
    if (low>high){              
        printf("Not found");
    }
     }
}

CircularQueue.c

#include <stdio.h>

#define MAX 3

int queue[MAX];
int front = -1;
int rear = -1;


void enqueue(int element){

    if (front == -1 && rear == -1){
   	 front = 0;  
   	 rear = 0;
   	 queue[rear] = element;  
   	 }
    else if((rear+1)%MAX == front){   
   	 printf("\nQueue overflow\n");
   	 }
    else{
   	 rear = (rear+1)%MAX;                 
   	 queue[rear] = element;          
    
    }
}

int dequeue(){
    if (front == -1 && rear == -1){
   	 printf("\nQueue underflow\n");
    }
    else if(front == rear){      
   	 printf("The dequeued element is %d",queue[front]);
   	 front = -1;
   	 rear = -1;
    }
    else{
    printf("\n The dequeued element is %d",queue[front]);
    front = (front+1)%MAX;   
    }
}

int display(){
    int i = front;
    if (front == -1 && rear ==-1){  
   	 printf("\nQueue is empty\n");
   	 }
    else if((rear+1)%MAX == front){    
   	 i = 0;
   	 while(i<MAX){
   		 printf("\n%d",queue[i]);
   		 i = i+1;
   	 }
    }
    else{
   	 printf("\n===========================\n");
   	 printf("Elements in the queue are");
   	 while(i<=rear){
   		 printf("\n%d",queue[i]);
   		 i = (i+1)%(MAX+front);    
   	 }
   	 printf("\n===========================\n");
    }
}


void main(){
    int choice = 1,x;
    while(choice < 4 && choice!=0){
   	 printf("\n===========================\n");
   	 printf("1.Insert into queue\n");
   	 printf("2.Delete from queue\n");
   	 printf("3.Display from queue\n");
   	 printf("4.Exit\n");
   	 printf("\n===========================\n");
   	 printf("Enter your choice");
   	 
   	 scanf("%d",&choice);
   	 switch(choice){
   		 case 1 : printf("Enter the element to be inserted");
   			 scanf("%d",&x);
   			 enqueue(x);
   			 break;
   		 case 2 : dequeue();
   			 break;
   		 case 3 : display();
   			 break;
   	 }
    }
}

Dequeue.c

#include <stdio.h>

#define MAX 10

int queue[MAX];
int front = -1, rear = -1;
void insert_rearend();
void insert_frontend();
void delete_rearend();
void delete_frontend();
void display();

void main(){
    int choice;
    do{
   	 printf("\n--------------------\n");
   	 printf("\n1.Insert at rear end\n");
   	 printf("\n2.Insert at front end\n");
   	 printf("\n3.Delete at rear end\n");
   	 printf("\n4.Delete at front end\n");
   	 printf("\n5.Display\n");
   	 printf("\n6.Exit\n");
   	 
   	 printf("Enter your choice");
   	 scanf("%d",&choice);
   	 
   	 switch(choice){
   		 case 1: insert_rearend();
   			 break;
   		 case 2: insert_frontend();
   			 break;
   		 case 3: delete_rearend();
   			 break;
   		 case 4: delete_frontend();
   			 break;
   		 case 5: display();
   			 break;
   	 }
    }while (choice!=6);
}



void insert_rearend(){
    int val;
    printf("Enter value to be added");
    scanf("%d",&val);   
    if ((front == 0 && rear == MAX-1) || (front == rear+1))  
   	 printf("OverFlow");
    if (front == -1){
   	 front = 0;  
   	 rear = 0;
    }
    else{
   	 if (rear == MAX-1) 
   		 rear = 0;      
   	 else
   		 rear = rear+1; 
    }
    queue[rear] = val;  

}

void insert_frontend(){

    int val;
    printf("Enter value to be added");
    scanf("%d",&val);
    if ((front == 0 && rear == MAX-1) || (front == rear+1))
   	 printf("OverFlow");
    if (front == -1){
   	 front = 0;
   	 rear = 0;
    }
    else{
   	 if (front == 0)     
   		 front = MAX-1;  
   	 else
   		 front = front -1; 
    }
    queue[front] = val;   
}

void delete_rearend(){
    if(front == -1){   
   	 printf("Underflow");
   	 return;
    }
    printf("Deleted Element is %d\n",queue[rear]);
    if (front ==rear){
   	 front = -1;  
   	 rear = -1;
    }
    else{
   	 rear = rear -1;   
    }
}

void delete_frontend(){
    if(front == -1){
   	 printf("Underflow");
   	 return;
    }
    printf("Deleted Element is %d\n",queue[front]);
    if (front ==rear){
   	 front = -1;
   	 rear = -1;
    }
    else{
   	 if (front == MAX -1)
   		 front = 0;
   	 else
   		 front = front+1;  
    }
}

void display(){
    if (front == -1){
   	 printf("\n queue is empty\n");
   	 return;
    }
    printf("\n The elements in queue are...\n");
    if(front <=rear){
   	 int tempFront = front;
   	 while(tempFront<=rear){
   		 printf("%d\t",queue[tempFront]);
   		 tempFront++;
   	 }
    }
    else{
   	 int tempFront = front;
   	 while(tempFront<=MAX-1){      
   		 printf("%d\t",queue[tempFront]);
   		 tempFront++;
   	 }
   	 tempFront = 0;
   	 while(tempFront<=rear){      
   		 printf("%d\t",queue[tempFront]);
   		 tempFront++;
   	 }
    }
    printf("\n");
}

LinearSearch.c

#include <stdio.h>

void main(){
    int A[50],len,i,j,key,flag=0;
    printf("Enter length of the array");
    scanf("%d",&len);
    
    printf("Enter elements in the array");
    for (i=0;i<len;i++){
   	 scanf("%d",&A[i]);
    }
    
    printf("Enter the element to be searched");
    scanf("%d",&key);
    for (i=0;i<len;i++){
   	 if (A[i]==key){
   		 flag=1;
   		 break;    
   	 }
    }
    if (flag==1){
   	 printf("Element found!");
    }
    else{
   	 printf("Element not found");
    }
}

Polynomials.c

#include <stdio.h>

void main(){
    int A[50][50],B[50],i,j;
    int polyno,polydegree;
    int maxpolydegree;
    printf("Enter number of polynomials\n");
    scanf("%d",&polyno);
    
    for(i=0;i<polyno;i++){
   	 printf("Enter Polynomial no %d\n",i+1);
   	 printf("Enter the degree of the polynomial\n");
   	 scanf("%d",&polydegree);
   	 if (polydegree>maxpolydegree)
   		 maxpolydegree = polydegree;
   	 for(j=0;j<=polydegree;j++){
   		 if (j==0){
   			 printf("Enter the constant\n");
   			 scanf("%d",&A[i][j]);}
   		 else{
   			 printf("Enter the coefficient of x^%d\n",j);
   			 scanf("%d",&A[i][j]);    
   		 }
   	 
   	 }
   	 
    }
    
    printf("Given polynomial data");
    for(i=0;i<polyno;i++){
   	 printf("\n");
   	 for(j=0;j<=maxpolydegree;j++){
   		 printf("%d \t",A[i][j]);

   	 
   	 }
   	 
    }
    
    for(i=0;i<=maxpolydegree;i++){
   	 for(j=0;j<=polyno;j++){
   		 B[i] += A[j][i];
   	 }    
    }
    
    printf("\nSum of the polynomials\n");
    
    for(i=maxpolydegree;i>=0;i--){
   	 if (i==0)
   		 printf("%d \t",B[i]);
   	 else
   		 printf("%d x^%d + ",B[i],i);
    
    }
    printf("\n");
    
    
    

}

PriorityQueue.c




#include<stdio.h>
#include<limits.h>
#define MAX 100
int idx = -1;
int pqVal[MAX];
int pqPriority[MAX];
int isEmpty()
{
    return idx == -1;
}
int isFull()
{
    return idx == MAX - 1;
}
void enqueue(int data, int priority)
{
    if(!isFull()){
        idx++;
        pqVal[idx] = data;             
        pqPriority[idx] = priority;
    }
}

int peek()
{
    int maxPriority = INT_MIN; 
    int indexPos = -1;
    for (int i = 0; i <= idx; i++)
    {
        if (maxPriority == pqPriority[i] && indexPos > -1 && pqVal[indexPos] < pqVal[i]){
            maxPriority = pqPriority[i];
            indexPos = i;
        }
        else if (maxPriority < pqPriority[i])  
                                               
        {
            maxPriority = pqPriority[i];      
            indexPos = i;     
        }
    }
    return indexPos;  
}

void dequeue()
{
    if(!isEmpty()){
        int indexPos = peek();   
        for (int i = indexPos; i < idx; i++){  
            pqVal[i] = pqVal[i + 1];           
            pqPriority[i] = pqPriority[i + 1];
        }
        idx--; 
    }
}

void display()
{
    for (int i = 0; i <= idx; i++)
        {
        printf("(%d, %d)\n",pqVal[i], pqPriority[i]);
        }
}
void main()
{
    int x,y,ch;
    do
    {
        printf("\t==== Menu ====\n");
        printf("\t 1. Enqueue\n");
        printf("\t 2. Dequeue\n");
        printf("\t 3. Display\n");
        printf("\t 0. Exit\n");
        printf("Your Choice :- \t");
        scanf("%d",&ch);
        switch(ch){
            case 1:
                printf("Enter value, its priority :- \n");
                scanf("%d%d",&x,&y);
                enqueue(x,y);
                break;
            case 2:
                dequeue();
                break;
            case 3:
                display();
                break;
            case 0:
                break;
            default:
                printf("Invalid Choice .....\n");
        }
    } while(ch != 0);
}

Queue.c

#include <stdio.h>
#include <stdlib.h>
#define MAX 5


int queue_array[MAX];

int rear = -1;
int front = -1;

void insert(){
    int item;
    if(rear == MAX-1)
   	 printf("\nQueue Overflow\n");
    else{
   	 if(front == -1)
   		 front = 0;  
   	 printf("\nInsert element in queue\n");
   	 scanf("%d",&item);
   	 rear = rear + 1;
   	 queue_array[rear] = item;   
    }
}

void delete(){
    if(front == -1 || front > rear){    
   	 printf("\nQueue underflow\n");
    }
    else{
   	 printf("\nElement deleted from queue is %d",queue_array[front]);
   	 front = front + 1;      
    }
}

void display(){
    int i;
    if (front == -1){
   	 printf("\nQueue is empty\n");
    }
    else{
   	 printf("\nQueue is..\n");
   	 for(i=front;i<=rear;i++){       
   		 printf("%d",queue_array[i]);
   		 printf("\n");
   	 
   	 }
    
    }


}
int main(){
    int choice;
    while(1){
   	 printf("\n1.Insert\n2.Delete\n3.Display\n4.Quit");
   	 printf("\nEnter your choice");
   	 scanf("%d",&choice);
   	 switch(choice){
   		 case 1:insert();
   			 break;
   		 case 2:delete();
   			 break;
   		 case 3:display();
   			 break;
   		 case 4:exit(0);
   			 break;
   	 
   	 }
    
    
    }
    
}

SparseMatrix.c

#include <stdio.h>

void main(){
	int a[50][50],n,m,i,j,count=0,k=0,b[3][20],countn=0;
	printf("Enter the no of row and columns");
	scanf("%d%d",&n,&m);
	printf("Enter elements in matrix");
	for(i=0;i<n;i++){
    	for(j=0;j<m;j++){
        	scanf("%d",&a[i][j]);
    	}
	}
	for(i=0;i<n;i++){
    	for(j=0;j<m;j++){
        	if(a[i][j]==0)
            	count = count+1;
        	else
            	countn++;
    	}
	}

	for(i=0;i<n;i++){
    	printf("\n");
    	for(j=0;j<m;j++){
        	printf("%d \t",a[i][j]);
    	}
	}

	if (count>(m*n)/2){
    		printf("\n Its a sparse matrix");
	}
	else{
    		printf("\n Its not a sparse matrix");
	}
	while(k!=countn){
    	for(i=0;i<3;i++){
        	for(j=0;j<m;j++){
            	if(a[i][j]!=0){
                	k++;
                	b[0][k-1]=i;
                	b[1][k-1]=j;
                	b[2][k-1] = a[i][j];
               	 
            	}
        	}
    	}
   	 
	}

	for(i=0;i<3;i++){
    	printf("\n");
    	for(j=0;j<countn;j++){
        	printf("%d\t",b[i][j]);
    	}
	}
}

Stack.c

#include <stdio.h>
#include <stdlib.h>
#define size 4

int top=-1,array[size];

void push(){
    int x;
    if (top==size-1)
   	 printf("\n Overflow!\n");
    else{
   	 printf("\n Enter element to be inserted to stack");
   	 scanf("%d",&x);
   	 top=top+1;
   	 array[top] = x;
    }
}

void pop(){
    if (top == -1)
   	 printf("\nUnderflow\n");
    else{
   	 printf("Popped element %d",array[top]);
   	 top = top-1;
    
    }
}

void show(){
    if (top == -1)
   	 printf("\nUnderflow\n");
    else{
   	 printf("\n Elements present in stack \n");
   	 for(int i=top;i>=0;--i)
   		 printf("%d \n",array[i]);
    
    }

}

void main(){
    int choice;
    while(1){
   	 printf("Operations performed by stack\n");
   	 printf("1.Push\n2.Pop\n3.Show\n4.End");
   	 printf("Enter the choice");
   	 scanf("%d",&choice);
   	 switch(choice){
   		 case 1:push();
   			 break;
   		 case 2:pop();
   			 break;
   		 case 3:show();
   			 break;
   		 case 4:exit(0);
   	 
   	 
   	 }
    }
}

binarytreelinkedlist.c

#include<stdio.h>
#include<stdlib.h>
typedef struct bin
    {
    int data;
    struct bin *left;
    struct bin *right;
} node;

void insert(node *, node *);
void inorder(node *);
void preorder(node *);
void postorder(node *);
int height(node *root);
void getLastNodeAndItsParent(node *root, int level, node *parent);
void deleteNode(node *root);
node *get_node();
node *lastNode, *parentOfLastNode;

void main()
{
    int choice;
    char ans = 'n';
    node *new, *root;
    root = NULL;
    do{
        printf("\n\t==== MENU ====\n");
        printf("\t 1. Create\n");
        printf("\t 2. Inorder\n");
        printf("\t 3. Pre-order\n");
        printf("\t 4. Post-Order\n");
        printf("\t 5. Delete A Node\n");
        printf("\t 6. Exit\n");
        printf("\nYour Choice :- \t");
        scanf("%d",&choice);
        switch(choice)
        {
            case 1:
                new = get_node();
                printf("\t Enter the element :- \t");
                scanf("%d",&new->data);
                if(root == NULL)
                    root = new;
                else
                    insert(root,new);
                break;
            case 2:
                if(root == NULL)
                    printf("Tree is not created, It is empty.\n");
                else
                    inorder(root);
                break;
            case 3:
                if(root == NULL)
                    printf("Tree is not created, It is empty.\n");
                else
                    preorder(root);
                break;
            case 4:
                if(root == NULL)
                    printf("Tree is not created, It is empty.\n");
                else
                    postorder(root);
                break;
            case 5:
                if(root == NULL)
                    printf("Tree is Empty, Cannot perform Deletion..\n");
                else
                    deleteNode(root);
                break;
            case 6:
                break;
            default:
                printf("Invalid Choice....\n");
        }
    }
    while(choice != 6);
}

node *get_node(){
        node *temp;
        temp = (node*) malloc(sizeof(node));
        temp->left = NULL;
        temp->right = NULL;
        return temp;
}

int height(node *root){
    int maximum, lheight, rheight;
    if (root == NULL)
    return 0;
    lheight = height(root->left) + 1;
    rheight = height(root->right) + 1;
    maximum = (lheight>rheight)?lheight:rheight;
    return maximum;
}

void getLastNodeAndItsParent(node *root, int level, node *parent)
{
    if (root == NULL)
        return;
    if (level == 1){
            lastNode = root;
            parentOfLastNode = parent;
    }
    getLastNodeAndItsParent(root->left, level - 1, root);
    getLastNodeAndItsParent(root->right, level - 1, root);
}
void insert(node *root, node *new){
    int ch;
    printf("\t Where to insert left/right of %d ? (L - 1/R - 2) :- \t",root->data);
    scanf("%d",&ch);
    if(ch == 2){
        if(root->right == NULL){
            root->right = new;
        }
        else{
            insert(root->right, new);
        }
    }
    else{
        if(root->left == NULL){
            root->left = new;
        }
        else{
            insert(root->left, new);
        }
    }
}

void deleteNode(node *root){
    int levelOfLastNode = height(root);
    getLastNodeAndItsParent(root, levelOfLastNode, NULL);
    if (lastNode && parentOfLastNode){
        if (parentOfLastNode->right){
            printf("Deleted Node is %d\n",(parentOfLastNode->right)->data);
            parentOfLastNode->right = NULL;
        }
        else{
            printf("Deleted Node is %d\n",(parentOfLastNode->left)->data);
            parentOfLastNode->left = NULL;
        }
    }
    else
    printf("\tEmpty Tree..\n");
}

void inorder(node *temp)
{
    if(temp != NULL){
        inorder(temp->left);
        printf("%d\t",temp->data);
        inorder(temp->right);
    }
}
void preorder(node *temp)
{
    if(temp != NULL){
        printf("%d\t",temp->data);
        inorder(temp->left);
        inorder(temp->right);
    }
}
void postorder(node *temp)
{
    if(temp != NULL){
        inorder(temp->left);
        inorder(temp->right);
        printf("%d\t",temp->data);
    }
}

infixtopostfixandeval.c

#define SIZE 50
#include <ctype.h>
#include <stdio.h>
#include <math.h>
char s[SIZE];
int top = -1;

void push(char elem){
        s[++top] = elem;
}
char pop(){
    return (s[top--]);
}
int priority(char elem)
    {
        switch (elem)
        {
        case '#':
        return 0;
        case '(':
        return 1;
        case '+':
        case '-':
        return 2;
        case '*':
        case '/':
        return 3;
        }
    }
void infix_to_postfix(char infix[], char postfix[]){
    char ch, elem;
    int i = 0, k = 0;
    push('#');                  
    while ((ch = infix[i++]) != '\n'){
        if (ch == '(')          
            push(ch);
        else if (isalnum(ch))   
            postfix[k++] = ch;
        else if (ch == ')'){    
            while (s[top] != '(')  
                postfix[k++] = pop();
            elem = pop();
        }
        else{ 
            while (priority(s[top]) >= priority(ch))  
                postfix[k++] = pop();
            push(ch);                                 
        }
    }
    while (s[top] != '#')                             
        postfix[k++] = pop();
    postfix[k] = 0;                                   
    }
    int eval_postfix(char *postfix)
    {
        char ch;
        int i = 0, op1, op2;
        while((ch = postfix[i++]) != 0)               
        {
            if(isdigit(ch))                           
                push(ch-'0');                         
            else
                {
                    op2 = pop();                      
                    op1 = pop();
                    switch(ch)
                    {
                    case '+' :
                        push(op1+op2);
                        break;
                    case '-' :
                        push(op1-op2);
                        break;
                    case '*' :
                        push(op1*op2);
                        break;
                    case '/' :
                        push(op1/op2);
                        break;
                    case '^':
                        push(pow(op1,op2));
                        break;
                    }
                }
        }
        return s[top];
}

char infx[50], pofx[50];
void main()
{
    printf("\nInput the infix expression: ");
    fgets(infx, 50, stdin);
    infix_to_postfix(infx, pofx);
    printf("\nGiven Infix Expression: %sPostfix Expression: %s", infx, pofx);
    top = -1;
    printf("\nResult of evaluation of postfix expression : %d\n", eval_postfix(pofx));
}

polynomialAddnMult.c

#include <stdio.h>
#include <stdlib.h>
struct poly{
    int coefficient;
    int exponential;
    struct poly *ptr;
};

struct poly *p =NULL,*q=NULL,*r=NULL;

struct poly *pptr,*qptr;

struct poly *add(struct poly *header,int coeff,int expo){
    struct poly *newnode,*temp=header;
    newnode = (struct poly*)malloc(sizeof(struct poly));
    newnode->coefficient = coeff;
    newnode->exponential = expo;
    newnode->ptr = NULL;
    
    if (header==NULL){
   	 header = newnode;
    }
    else{
   	 while(temp->ptr!=NULL){
   		 temp = temp -> ptr;
   	 }
    temp -> ptr = newnode;
    return header;
    }
}
void display(struct poly *header){
    struct poly *current = header;
    if(header==NULL)
   	 printf("list is empty");
    else{
   	 while(current!=NULL){
   		 if(current->ptr!=NULL){
   			 printf(" %d x^%d +",current->coefficient,current->exponential);
   		 }
   		 else{
   			 printf(" %d x^%d",current->coefficient,current->exponential);
   		 }
   		 current = current->ptr;
   	 }
    }
}

void addition(struct poly *p,struct poly *q){
    int result;
    pptr= p,qptr = q;
    if(pptr==NULL){
   	 printf("pptr is null");
    }
    while((pptr!=NULL)&&(qptr!=NULL)){
   	 if (pptr->exponential > qptr->exponential){
   		 printf("abc");
   		 r = add(r,pptr->coefficient,pptr->exponential);
   		 pptr = pptr -> ptr;
   		 
   	 }
   	 else if(pptr->exponential < qptr->exponential){
   		 printf("abc");
   		 r = add(r,qptr->coefficient,qptr->exponential);
   		 qptr = qptr->ptr;
   	 }
   	 else{
   		 result = qptr->coefficient,qptr->coefficient;
   		 r= add(r,pptr->coefficient+qptr->coefficient,pptr -> exponential);
   		 qptr = qptr->ptr;
   		 pptr = pptr->ptr;
   	 }
    }
    while(pptr!=NULL){
   	 r=add(r,pptr->coefficient,pptr->exponential);
   	 pptr = pptr->ptr;
    }
    while(qptr!=NULL){
   	 r=add(r,qptr->coefficient,qptr -> exponential);
   	 
   	 qptr = qptr->ptr;
    }
    
}
    
struct poly *sort_add(struct poly *header,int coeff,int expo){
   	 
   	 struct poly *next = header,*prev = NULL;
   	 struct poly *newnode;
   	 newnode = (struct poly *) malloc(sizeof(struct poly*));
   	 newnode -> coefficient = coeff;
   	 newnode -> exponential = expo;
   	 newnode -> ptr=NULL;
   	 if(header == NULL){
   		 header = newnode;
   	 }
   	 else{
   		 while(next!=NULL && next -> exponential > expo){
   			 prev = next;
   			 next = next ->ptr;
   		 }
   		 if(prev == NULL){
   			 if (next ->exponential ==expo){
   				 next -> coefficient = coeff+ next->coefficient;
   				 free(newnode);
   			 }
   			 else{
   				 newnode -> ptr = next;
   				 header = newnode;
   			 }
   		 }
   		 else{
   			 if((next!=NULL) && (next ->exponential ==expo)){
   				 next -> coefficient = next -> coefficient +coeff;
   				 free(newnode);
   			 }
   			 else{
   				 prev -> ptr = newnode;
   				 newnode -> ptr = next;
   			 
   			 }
   			 
   		 }
   		 return header;
   	 }
   	 
    }
void multiplication(struct poly *p,struct poly *q){
   	 int coeff,expo;
   	 pptr=p;
   	 qptr = q;
   	 while(pptr!=NULL){
   		 qptr = q;
   		 while(qptr!=NULL){
   			 coeff = pptr->coefficient * qptr->coefficient;
   			 expo = pptr->exponential + qptr->exponential;
   			 r= sort_add(r,coeff,expo);
   			 qptr = qptr -> ptr;
   		 }
   		 pptr = pptr->ptr;
   	 }
   	 
}
    
    
void main(){
    int a,n,coeff,expo;
    //printf("polynomial representation");
    printf("Enter number of elements in 1st polynomial");
    scanf("%d",&n);
    
    for(int i=0;i<n;i++){
   	 printf("Enter coefficient ");
   	 scanf("%d",&coeff);
   	 printf("Enter exponential ");
   	 scanf("%d",&expo);
   	 p = add(p,coeff,expo);
   	 printf("\n");
    }
    printf("Enter no of elements in 2nd polynomial");
    scanf("%d",&n);
    for(int i=0;i<n;i++){
   	 printf("Enter the coefficient");
   	 scanf("%d",&coeff);
   	 printf("Enter exponential");
   	 scanf("%d",&expo);
   	 q = add(q,coeff,expo);
   	 printf("\n");
    }
    printf("Polynomial 1 is ");
    display(p);
    printf("\n");
    printf("Polynomial 2 is ");
    display(q);
    printf("\n 1.Addition \n 2. Multiplication ");
    scanf("%d",&a);
    switch(a){
    case 1: addition(p,q);
    	printf("The result is");
    	display(r);
   	 break;
    case 2: multiplication(p,q);
    	printf("The result is");
    	display(r);
   	 break;
    default: printf("Invalid Choice");
   	 break;
    }
    
}

singlylinkedlist.c

#include<stdlib.h>
#include<stdio.h>
void display();
void insert_begin();
void insert_end();
void insert_pos();
void delete_begin();
void delete_end();
void delete_pos();

struct node{
    int info;
    struct node *next;

};

struct node *start = NULL;

int main(){
    int choice;
	printf("\n Menu \n");
	printf("\n1.Display");
	printf("\n2.Insert at the beginning");
	printf("\n3.Insert at the end");
	printf("\n4.Insert at specified position");
	printf("\n5.Delete from beginning");
	printf("\n6.Delete from the end");
	printf("\n7.Delete from specific position");
	printf("\n8.Exit");
    while(1){
   	 printf("\n Enter your choice");
   	 scanf("%d",&choice);
   	 switch(choice){
   		 case 1: display();
   			 break;
   		 case 2: insert_begin();
   			 break;
   		 case 3: insert_end();
   			 break;
   		 case 4: insert_pos();
   			 break;
   		 case 5: delete_begin();
   			 break;
   		 case 6: delete_end();
   			 break;
   		 case 7: delete_pos();
   			 break;
   		 case 8: exit(0);
   			 break;
   		 default: printf("\n Wrong choice");
   	 }
   		 
    
    }
    return 0;

}

void display(){
    struct node *ptr;
    if(start==NULL){
   	 printf("\n List is empty");
   	 return;
    }
    else{
   	 ptr=start;
   	 printf("In the list elements are\n");
   	 while(ptr!=NULL){
   		 printf("%d\t",ptr->info);
   		 ptr=ptr->next;
   	 }
    }
}

void insert_begin(){
    struct node *temp;
    temp = (struct node*)malloc(sizeof(struct node));
    if(temp==NULL){
   	 printf("\n Overflow");
   	 return;
    }
    
    printf("\n Enter the data value of the node \t");
    scanf("%d",&temp->info);
    temp->next = NULL;
    if(start==NULL)
   	 start = temp;
    else{
   	 temp->next=start;
   	 start = temp;
    }
}

void insert_end(){
    struct node *temp,*ptr;
    temp = (struct node*)malloc(sizeof(struct node));
    
    if(temp==NULL){
   	 printf("\n Overflow");
   	 return;
    }
    
    printf("\n Enter the data value of the node \t");
    scanf("%d",&temp->info);
    temp->next = NULL;
    if(start==NULL)
   	 start = temp;
    else{
   	 ptr=start;
   	 while(ptr->next!=NULL){
   		 ptr=ptr->next;   	 
   	 }
   	 ptr->next = temp;
    }
}

void insert_pos(){
    struct node *ptr,*temp;
    int i,pos;
    temp = (struct node*)malloc(sizeof(struct node));
    
    if(temp==NULL){
   	 printf("\n Overflow");
   	 return;
    }
    
    printf("\n Enter the position for the new node to be inserted \t");
    scanf("%d",&pos);
    printf("\n Enter the data value of the node \t");
    scanf("%d",&temp->info);
    temp->next = NULL;
    
    if(pos==0){
   	 temp->next=start;
   	 start = temp;
    }
    else{
   	 for(i=0,ptr=start;i<pos-1;i++){
   		 ptr = ptr->next;
   		 if(ptr==NULL){
   			 printf("\n Position not found");
   			 return;
   		 }
   	 }
   	 temp->next = ptr->next;
   	 ptr->next = temp;
    }
}


void delete_begin(){
    struct node *ptr;
    if(start==NULL){
   	 printf("\n Underflow");
   	 return;
    }
    else{
   	 printf("1");
   	 ptr=start;
   	 printf("2");
   	 start = start->next;
   	 printf("\n The deleted element is %d \t",ptr->info);
   	 free(ptr);
    }

}

void delete_end(){
    struct node *temp, *ptr;
    if(start==NULL){
   	 printf("\n Underflow");
   	 return;
    }
    else if(start->next==NULL){
   	 ptr=start;
   	 start=NULL;
   	 printf("\n The deleted element is %d",ptr->info);
   	 free(ptr);
    }
    else{
   	 ptr=start;
   	 while(ptr->next!=NULL){
   		 temp = ptr;
   		 ptr=ptr->next;
   	 }
   	 temp->next = NULL;
   	 printf("\n The deleted element is %d \t",ptr->info);
   	 free(ptr);
    }
}

void delete_pos(){
    int i,pos;
    struct node *ptr, *temp;
    if(start==NULL){
   	 printf("\n Underflow");
   	 exit(0);
    }
    else{
   	 printf("\n Enter the position to be deleted");
   	 scanf("%d",&pos);
   	 if(pos == 0){
   		 ptr = start;
   		 start = start->next;
   		 printf("\n The deleted element is %d \t",ptr->info);
   		 free(ptr);
   	 }
   	 else{
   		 ptr = start;
   		 for(i=0;i<pos;i++){
   			 temp = ptr;
   			 ptr = ptr->next;
   			 if(ptr == NULL){
   				 printf("\n Position not found");
   				 return;
   			 }
   		 
   		 }
   		 temp->next = ptr->next;
   		 printf("\n The deleted element is %d \t",ptr->info);
   		 free(ptr);
   	 }
    
    }
}