Develop a ‘C’ program to create and implement a CIRCULAR QUEUE using arrays.

 

DATA STRUCTURE & ALGORITHM USING C – LAB (2018407)

UNIT – 07

Develop a ‘C’ program to create and implement a CIRCULAR QUEUE using arrays.

Program:

#include<stdio.h>
#include<conio.h>
#define SIZE 5
void enQueue(int);
void deQueue();
void display();
int cQueue[SIZE], front = -1, rear = -1;
void main()
{
   int choice, value;
   clrscr();
   while(1){
      printf("\n****** MENU ******\n");
      printf("1. Insert\n2. Delete\n3. Display\n4. Exit\n");
      printf("Enter your choice: ");
      scanf("%d",&choice);
      switch(choice){
  case 1: printf("\nEnter the value to be insert:  ");
   scanf("%d",&value);
   enQueue(value);
   break;
  case 2: deQueue();
   break;
  case 3: display();
   break;
  case 4: exit(0);
  default: printf("\nPlease select the correct choice!!!\n");
      }
   }
}
void enQueue(int value)
{
   if((front == 0 && rear == SIZE - 1) || (front == rear+1))
      printf("\nCircular Queue is Full! Insertion not possible!!!\n");
   else{
      if(rear == SIZE-1 && front != 0)
  rear = -1;
      cQueue[++rear] = value;
      printf("\nInsertion Success!!!\n");
      if(front == -1)
  front = 0;
   }
}
void deQueue()
{
   if(front == -1 && rear == -1)
      printf("\nCircular Queue is Empty! Deletion is not possible!!!\n");
   else{
      printf("\nDeleted element : %d\n",cQueue[front++]);
      if(front == SIZE)
  front = 0;
      if(front-1 == rear)
  front = rear = -1;
   }
}
void display()
{
   if(front == -1)
      printf("\nCircular Queue is Empty!!!\n");
   else{
      int i = front;
      printf("\nCircular Queue Elements are : \n");
      if(front <= rear){
  while(i <= rear)
     printf("%d\t",cQueue[i++]);
      }
      else{
  while(i <= SIZE - 1)
     printf("%d\t", cQueue[i++]);
  i = 0;
  while(i <= rear)
     printf("%d\t",cQueue[i++]);
      }
   }
}