C语言数据结构四：栈的链式存储

前面是用数组实现栈，现在考虑用链表来实现栈。

首先考虑先进后出这一原则，数据从哪头出最好？如果选择数组那样的结尾做栈顶，那么需要遍历整个链表才可以出栈入栈。所以最方便的还是让头结点作为栈顶。通过链表的next执行后续出栈入栈即可。

还是先在头文件中建立结构体：首先是链表是由结点构成，定义链表的结点数据结构体。然后是链表的结构体。包含头结点。然后增加一个size属性。

struct StackNode
{
	struct StackNode *next;
};


struct LStack
{
	struct StackNode header; //头结点
	int size;
};

考虑到初始化时，我们对链表数据的保护，我们定义一种隐藏类型。

typedef void* LinkStack;

#pragma once

#include<stdlib.h>
#include"LinkList.h"

struct StackNode
{
	struct StackNode *next;
};


struct LStack
{
	struct StackNode header; //头结点
	int size;
};

typedef void* LinkStack;

#ifdef __cplusplus
extern "C"{
#endif	

	//初始化
	LinkStack Init_LinkStack();
	//入栈
	void Push_LinkStack(LinkStack stack, void *data);
	//出栈
	void Pop_LinkStack(LinkStack stack);
	//获得栈顶元素
	void* Top_LinkStack(LinkStack stack);
	//获得大小
	int Size_LinkStack(LinkStack stack);
	//销毁栈
	void Destroy_LinkStack(LinkStack stack);

#ifdef __cplusplus
}
#endif	

代码实现

#include"LinkStack.h"


//初始化
LinkStack Init_LinkStack()
{


	struct LStack *stack = malloc(sizeof(struct LStack));
	if (NULL == stack)
	{
		return NULL;
	}

	stack->header.next = NULL;
	stack->size = 0;

	return stack;

}
//入栈
void Push_LinkStack(LinkStack stack, void *data)
{

	if (NULL == stack)
	{	
		return;
	}

	if (NULL == data)
	{
	
		return;
	}
	// 入栈参数先类型转换，然后把数据data也做转换赋值给链表的next。
	struct LStack *ls = (struct LStack *)stack;
	struct StackNode *node = (struct StackNode *)data;


	node->next = ls->header.next;
	ls->header.next = node;

	++(ls->size);

}
//出栈
void Pop_LinkStack(LinkStack stack)
{
	if (NULL == stack)
	{
		return;
	}
	//入栈参数链表先类型转换
	struct LStack *ls = (struct LStack *)stack;

	if (ls->size == 0)
	{
		return;
	}

	//缓存下第一个节点
	struct StackNode *pFirst = ls->header.next;
	// 出栈就是把头结点弹出去，将头结点的next做头结点。
	ls->header.next = pFirst->next;

	ls->size--;
}
//获得栈顶元素
void* Top_LinkStack(LinkStack stack)
{
	if (NULL == stack)
	{
		return NULL;
	}

	struct LStack *ls = (struct LStack *)stack;

	if (ls->size == 0)
	{
		return NULL;
	}


	return ls->header.next;
}
//获得大小
int Size_LinkStack(LinkStack stack)
{
	if (NULL == stack)
	{
		return -1;
	}

	struct LStack *ls = (struct LStack *)stack;

	return ls->size;
}
//销毁栈
void Destroy_LinkStack(LinkStack stack)
{

	if (NULL == stack)
	{
		return;
	}

	free(stack);
	stack = NULL;
}

验证代码

#define _CRT_SECURE_NO_WARNINGS
#include<stdio.h>
#include<string.h>
#include<stdlib.h>
#include"LinkStack.h"

struct Person
{
	struct StackNode node;
	char name[64];
	int age;
};

void test()
{

	//初始化栈
	LinkStack stack = Init_LinkStack();
	
	//创建数据
	struct Person p1 = { NULL, "aaa", 10 };
	struct Person p2 = { NULL, "bbb", 20 };
	struct Person p3 = { NULL, "ccc", 30 };
	struct Person p4 = { NULL, "ddd", 40 };
	struct Person p5 = { NULL, "eee", 50 };
	struct Person p6 = { NULL, "fff", 60 };

	//数据入栈
	Push_LinkStack(stack, &p1);
	Push_LinkStack(stack, &p2);
	Push_LinkStack(stack, &p3);
	Push_LinkStack(stack, &p4);
	Push_LinkStack(stack, &p5);
	Push_LinkStack(stack, &p6);

	//输出栈中所有元素
	while (Size_LinkStack(stack) > 0)
	{

		//获得栈顶元素
		struct Person *person = (struct Person *)Top_LinkStack(stack);
		//打印
		printf("Name:%s Age:%d\n", person->name, person->age);
		//弹出栈顶元素
		Pop_LinkStack(stack);

	}

	printf("Size:%d\n", Size_LinkStack(stack));

}

int main(){

	test();

	system("pause");
	return EXIT_SUCCESS;
}