1// Aim: Program to perform Queue operations (Insertion, Deletion).
2#include<stdio.h>
3int a[20],size,front,rear;
4void insert(int item){
5    if(rear==size-1){
6        printf("Queue is full\n");
7    }
8    else if(rear==-1){
9        front=rear=0;
10        a[rear]=item;
11    }
12    else{
13        rear++;
14        a[rear]=item;
15    }
16}
17void delete(){
18    if(front==-1){
19        printf("Queue is empty\n");
20    }
21    else if(front==rear){
22        printf("Deleted element is %d\n",a[front]);
23        front=rear=-1;
24    }
25    else{
26        printf("Deleted element is %d\n",a[front]);
27        front++;
28    }
29}
30void display(){
31    int i;
32    if(front==-1){
33        printf("Queue is empty\n");
34    }
35    else{
36        for(i=front;i<=rear;i++){
37            printf("%d\t",a[i]);
38        }
39    }
40}
41
42void main(){
43    int ch,item;
44    printf("Enter the size of the queue\n");
45    scanf("%d",&size);
46    front=rear=-1;
47    do{
48        printf("\n1.Insert\n2.Delete\n3.Display\n4.Exit\n");
49        printf("Enter your choice\n");
50        scanf("%d",&ch);
51        switch(ch){
52            case 1: printf("Enter the element to be inserted\n");
53                    scanf("%d",&item);
54                    insert(item);
55                    break;
56            case 2: delete();
57                    break;
58            case 3: display();
59                    break;
60            case 4: break;
61            default: printf("Invalid choice\n");
62        }
63    }while(ch!=4);
64}