queueusingarr.c

#include <stdio.h>
#include <conio.h>
#define SIZE 10

void enQueue(int);
void deQueue();
void display();

int queue[SIZE], front = -1, rear = -1;

void main()
{
   int value, choice;
   while (1)
   {
      printf("\n\n***** MENU *****\n");
      printf("1. Insertion\n2. Deletion\n3. Display\n4. Exit");
      printf("\nEnter your choice: ");
      scanf("%d", &choice);
      switch (choice)
      {
      case 1:
         printf("Enter the value to be insert: ");
         scanf("%d", &value);
         enQueue(value);
         break;
      case 2:
         deQueue();
         break;
      case 3:
         display();
         break;
      case 4:
         exit() : 
         default : printf("\nWrong selection!!! Try again!!!");
      }
   }
}
void enQueue(int value)
{
   if (rear == SIZE - 1)
      printf("\nQueue is Full!!! Insertion is not possible!!!");
   else
   {
      if (front == -1)
         front = 0;
      rear++;
      queue[rear] = value;
      printf("\nInsertion success!!!");
   }
}
void deQueue()
{
   if (front == rear)
      printf("\nQueue is Empty!!! Deletion is not possible!!!");
   else
   {
      printf("\nDeleted : %d", queue[front]);
      front++;
      if (front == rear)
         front = rear = -1;
   }
}
void display()
{
   if (rear == -1)
      printf("\nQueue is Empty!!!");
   else
   {
      int i;
      printf("\nQueue elements are:\n");
      for (i = front; i <= rear; i++)
         printf("%d\t", queue[i]);
   }
}