数据结构——队列

大家好我是小锋，今天我们来学习队列。

队列的概念及结构

实现队列

我们首先要创建一个链表结构，用于存储数据，然后创建一个队列结构用于记录队列的基础数据

我们创建一个链表结构和队列结构的指针，（还是分装在一个测试函数中）

下面我们才开始进行队列操作

初始化

//初始化
void Queueinit(Queue *por) {
	assert(por);
	por->ps = NULL;
	por->pt = NULL;
	por->size = 0;
}

队尾入队列

//队尾入队列
void Queuepush(Queue* por, CMMlet n) {
	assert(por);
	Qnode* cur = (Qnode*)malloc(sizeof(Qnode));
	if (cur == NULL) {
		printf("%s", trerror(errno));
		return 0;
	}
	cur->sz = n;
	cur->next = NULL;
	if (por->ps) {
		por->pt->next = cur;
		por->pt = por->pt->next;
	}
	else {
		assert(por->pt == NULL);
		por->ps->next= cur;
		por->pt->next= cur;
	}
	por->size++;
}

对头出队列

//对头出对列
void queuepop(Queue* por) {
	assert(por);
	//assert(por->ps && por->ps->next);
	if (por->ps->next==NULL) {
		free(por->ps);
		por->ps = NULL;
		por->pt = NULL;
	}
	else {
		Qnode* cur = por->ps->next;
		free(por->ps);
		por->ps = cur;
	}
	por->size--;
}

获取头部元素

//获取头部元素
CMMlet queuetop(Queue* por) {
	assert(por);
	assert(Empty(por));
	return por->ps->sz;
}

布尔判断

//bool判断
bool Empty(Queue* por) {
	assert(por);
	return por->size;
}

判断队列是否为空

获取队列中有效元素个数

//获取队列中有效元素个数

int queuesize(Queue* por) {
	assert(por);
	return por->size;
}

销毁队列

// 销毁队列
void queueDestroy(Queue*por) {
	assert(por);
	Qnode* cur = por->ps;
	while (cur) {
		Qnode* add = cur->next;
		free(cur);
		cur = add;
	}
	por->ps = NULL;
	por->pt = NULL;
	por->size = 0;
}

我们可以来测试一下这个队列

下面是本节所有的代码大家可以试试

# define _CRT_SECURE_NO_WARNINGS
# include<stdio.h>
# include<assert.h>
# include<stdlib.h>
# include<string.h>
# include<errno.h>
# include<stdbool.h>

typedef struct Qlistnode Qnode;
typedef struct Queue Queue;
typedef int CMMlet;
//队列实现
// 
//链表结构
struct Qlistnode {
	CMMlet sz;//存储的数据
	struct Qlistnode* next;//下个节点
};
//队列结构
struct Queue {
    Qnode *ps;//队头
	Qnode *pt;//队尾
	int size;//队列元素个数
};

//初始化
void Queueinit(Queue *por) {
	assert(por);
	por->ps = NULL;
	por->pt = NULL;
	por->size = 0;
}

//bool判断
bool Empty(Queue* por) {
	assert(por);
	return por->size;
}


//队尾入队列
void queuepush(Queue* por, CMMlet n) {
	assert(por);
	Qnode* cur = (Qnode*)malloc(sizeof(Qnode));
	if (cur == NULL) {
		printf("%s", strerror(errno));
		return;
	}
	cur->sz = n;
	cur->next = NULL;
	if (por->ps) {
		por->pt->next = cur;
		por->pt = por->pt->next;
	}
	else {
		assert(por->pt == NULL);
		por->ps= cur;
		por->pt= cur;
	}
	por->size++;
}


//对头出对列
void queuepop(Queue* por) {
	assert(por);
	//assert(por->ps && por->ps->next);
	if (por->ps->next==NULL) {
		free(por->ps);
		por->ps = NULL;
		por->pt = NULL;
	}
	else {
		Qnode* cur = por->ps->next;
		free(por->ps);
		por->ps = cur;
	}
	por->size--;
}

//获取头部元素
CMMlet queuetop(Queue* por) {
	assert(por);
	assert(Empty(por));
	return por->ps->sz;
}



//获取队列中有效元素个数

int queuesize(Queue* por) {
	assert(por);
	return por->size;
}



// 销毁队列
void queueDestroy(Queue*por) {
	assert(por);
	Qnode* cur = por->ps;
	while (cur) {
		Qnode* add = cur->next;
		free(cur);
		cur = add;
	}
	por->ps = NULL;
	por->pt = NULL;
	por->size = 0;
}


//打印队列
void queuedy(Queue* por) {
	Qnode* cur = por->ps;
	printf("队头->");
	while (cur) {
		printf("%d->", cur->sz);
		cur = cur->next;
	}
	printf("->队尾\n");
}

//测试函数
void queuecs() {
	Qnode* head = NULL;
	Queue pead;
	Queueinit(&pead);
	queuepush(&pead, 1);
	queuepush(&pead, 2);
	queuepush(&pead, 3);
	queuepush(&pead, 4);
	queuepush(&pead, 5);
	queuedy(&pead);
	queuepop(&pead);
	queuepop(&pead);
	queuepop(&pead);
	queuedy(&pead);
	int n = queuetop(&pead);
	printf("%d\n",n);
	n = queuesize(&pead);
	printf("%d\n", n);
	queueDestroy(&pead);



}

int main() {
	queuecs();
	return 0;
}

    以上就是全部内容了，如果有错误或者不足的地方欢迎大家给予建议。