queue

#include<stdio.h>
#define MAX 50

void insert();
void delete();
void display();
int queue_array[MAX];
int rear=-1;
int front=-1;
int main()
{
    int choice;
    while(1)
    {
        printf("1.insert element to queue \n");
        printf("2.delete element from queue \n");
        printf("3.Display all elements of queue \n");
        printf("4.Quit \n");
        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 add_item;
    if (rear==MAX-1)
          printf("Queue Overflow \n");
    else
    {
        if(front==-1)

            front=0;
            printf("Insert   the element in queue : ");
            scanf("%d",&add_item);
            rear=rear+1;
            queue_array[rear]=add_item;

    }

}
void delete()
{
    if(front==-1||front>rear)
    {
        printf("Queue Underflow \n");
        return ;

    }
    else
    {
        printf("Element deleted from queue is: %d\n",queue_array[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  ",queue_array[i]);
        printf("\n");
    }

}