Circle Queue in C

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<!-- lang: cpp -->
#include "stdafx.h"
#include <iostream>
#include <malloc.h>

struct CircleQueue{
	int head;
	int tail;
	int length;
	int isFull;
	int *array;
};

CircleQueue* CreatCircleQueue(int length){
	CircleQueue *q = (CircleQueue*)malloc(sizeof(struct CircleQueue));
	q->length = length;
	q->tail = 0;
	q->head = 0;
	q->array = (int *)malloc(sizeof(int)*length);
	q->isFull = 0;
	return q;
}

int EnterQueue(CircleQueue* q,int x){
	if(q->isFull == -1){
		printf("\nError: The Circle Queue is full!\n");
		return -1;
	}else{
		q->head = q->head + 1;
		if(q->head > q->length - 1)
			q->head = 0;
		if(q->head == q->tail)
			q->isFull = -1;
		q->array[q->head] = x;
	}
	return 0;
}    

int DelQueue(CircleQueue * q){
	if(q->isFull == 0 && q->head == q->tail){
		printf("Error: The Circle Queue is Empty!\n");
		return -1;
	}else{
		q->tail = q->tail + 1;
		if(q->tail > q->length-1)	
			q->tail = 0;
		if(q->tail == q->head)
			q->isFull = 0;

		return 0;
	}
}

int ShowQueue(CircleQueue* q){
	int i,j;
	int flag = 1;
	if(q->isFull == 0 && q->head == q->tail){
		//printf("Queue is Empty!\n");
	}else{
		i = q->head;
		while(1){
			printf(" %d ",q->array[i--]);
			if(i<0)	i=9;
			if(i == q->tail)	break;
		}
		printf("\n");
	}

	return 0;
}    

int main(){
	CircleQueue *q = CreatCircleQueue(10);
	int i,j;
	for(j=1;j<=3;j++){
		for(i=1;i<=5;i++){
			EnterQueue(q,i*j);
			ShowQueue(q);
		}

		for(i=1;i<=5;i++){
			DelQueue(q);
			ShowQueue(q);
		}
	}

	getchar();
	return 0;
}    

转载于:https://my.oschina.net/dongdong2012/blog/115464