circular_queue.cpp

#include <stdio.h>
#include <stdlib.h>
struct Queue
{
 int size;
 int front;
 int rear;
 int *Q;
};
void create(struct Queue *q,int size)
{
 q->size=size;
 q->front=q->rear=0;
 q->Q=(int *)malloc(q->size*sizeof(int));
}
void enqueue(struct Queue *q,int x)
{
 if((q->rear+1)%q->size==q->front)
 printf("Queue is Full");
 else
 {
 q->rear=(q->rear+1)%q->size;
 q->Q[q->rear]=x;
 }
}
int dequeue(struct Queue *q)
{
 int x=-1;
 
 if(q->front==q->rear)
 printf("Queue is Empty\n");
 else
 {
 q->front=(q->front+1)%q->size;
 x=q->Q[q->front];
 }
 return x;
}
void Display(struct Queue q)
{
 int i=q.front+1;
 
 do
 {
 
 printf("%d ",q.Q[i]);
 i=(i+1)%q.size;
 }while(i!=(q.rear+1)%q.size);
 
 printf("\n");
}
int main()
{
 struct Queue q;
 create(&q,5);
 
 enqueue(&q,10);
 enqueue(&q,20);
 enqueue(&q,30);
 enqueue(&q,40);
 enqueue(&q,50);
 enqueue(&q,60);
 Display(q);
 
 printf("%d ",dequeue(&q));
 return 0; }