Queue.c

#include <stdio.h>
#include<stdlib.h>
 
#define MAX 5
void insert();
void delete();
void display();
int q[MAX];
int rear = - 1;
int front = - 1;
main()
{
    int choice;
        printf(" 1.Insert element to queue \n 2.Delete element from queue \n 3. Display element from queue \n 4.Exit \n ");
      while(1)
      {
      	printf("Enter your choice : ");
        scanf("%d", &choice);
        switch (choice)
        {
            case 1:
            insert();
            break;
            case 2:
            delete();
            break;
            case 3:
            display();
            break;
            case 4:
            exit(1);
            default:
            printf("Wrong choice \n");
        }
    } 
}
void insert()
{
    int elm;
    if (rear == MAX - 1)
    printf("Queue Overflow \n");
    else
    {
        if (front == - 1)
        front = 0;
        printf("Inset the element in queue : ");
        scanf("%d", &elm);
        rear = rear + 1;
        q[rear] = elm;
    }
}
 
void delete()
{
    if (front == - 1 || front > rear)
    {
        printf("Queue Underflow \n");
        return;
    }
    else
    {
        printf("Element deleted from queue is : %d\n", q[front]);
        front = front + 1;
    }
}
void display()
{
    int i;
    if (front == - 1)
        printf("Queue is empty \n");
    else
    {
        printf("Queue is : \n");
        for (i = front; i <= rear; i++)
            printf("%d ", q[i]);
        printf("\n");
    }
}