Queue

// Queue

#include<stdio.h>
#include<conio.h>
#define MAX 5
int ch,front=-1,rear=-1,queue[MAX],item;
void main()
{
 clrscr();
 while(1)
 {
  printf("*** Menu ***\n 1. Insert\n 2. Delete\n 3. Display\n 4. Exit\n");
  printf("Enter your choice");
  scanf("%d",&ch);
  switch(ch)
  {
   case 1: insert();
  break;
   case 2: del();
  break;
   case 3: display();
  break;
   case 4: exit();
   default:
  printf("You are out of choice!");
   }
  }
}

int insert()
{
 int added_item;
 if(rear==MAX-1)
  printf("Queue overflow i.e. full!");
 else
 {
  if(front==-1)  //If queue is initially empty
  front=0;
  printf("Enter the item to adding in the queue");
  scanf("%d",&added_item);
  rear++;
  queue[rear]=added_item;
  }
  return 0;
}

int del()
{
 if(front==-1||front>rear)
 {
  printf("Queue is underflow i.e. empty\n");
 }
 else
 {
  printf("The deleted item from queue is %d\n",queue[front]);
  front++;
 }
 return 0;
}

int display()
{
 int i;
 if(front==-1)
  printf("Queue is underflow!");
 else
 {
  printf("Queue display\n");
  for(i=front;i<=rear;i++)
  {
   printf("%d",queue[i]);
  }
  printf("\n");
 }
 return 0;
}