C语言数据结构——队列

C语言数据结构——队列

#include <stdio.h>
#include <string.h>
#include <stdlib.h>
#define MAXSIZE 100

typedef int ElemType; 

typedef struct{
	ElemType *data;
	int front;
	int rear;
}Queue; 

Queue* initQueue()
{
	Queue *q = (Queue*)malloc(sizeof(Queue));
	q->data = (ElemType*)malloc(sizeof(ElemType) * MAXSIZE);
	q->rear = 0;
	q->front = 0;
	return q;
}
//初始化队列

int isEmpty(Queue *q)
{
	if(q->front == q->rear)
	{
		printf("Empty.\n");
		return 1;
	}
	else
	{
		return 0;
	}
}
//判断队列是否为空

int queueFull(Queue *q)
{
	if(q->front > 0)
	{
		int step = q->front;
		for(int i = q->front; i <= q->rear; ++i)
		{
			q->data[i - step] = q->data[i];
		}
		q->front = 0;
		q->rear = q->rear - step;
		return 1;
	}
	else
	{
		printf("Full.\n");
		return 0;
	}
}
//调整队列（时间复杂度过高，所以继续学习循环队列）

int getHead(Queue *q,ElemType *e)
{
	if(q->rear == q->front)
	{
		printf("Empty.\n");
		return 0;
	}
	*e = q->data[q->front];
	return 1;
}
//获取头元素

int eQueue(Queue *q,ElemType e)
{
	if(q->rear >= MAXSIZE)
	{
		if(!queueFull(q))
		{
			return 0;
		}
	}
	q->data[q->rear] = e;
	q->rear++;
	return 1;
}
//入队

ElemType deQueue(Queue *q)
{
	if(q->front == q->rear)
	{
		printf("Empty.\n");
		return 0;
	}
	ElemType e = q->data[q->front];
	q->front++;
	return e;
}
//出队

int main()
{
	Queue *q;
	q = initQueue();
	eQueue(q,10);
	eQueue(q,20);
	eQueue(q,30);
	eQueue(q,40);
	eQueue(q,50);
	printf("%d\n",deQueue(q));
	printf("%d\n",deQueue(q));
	ElemType e;
	getHead(q,&e);
	printf("%d\n",e);
	return 0;
}