链栈

#include <stdio.h>
#include <malloc.h>
#include <stdlib.h>

typedef int T;
typedef struct StackNode
{
    
	T data;//数据
	StackNode* next;//指向下一结点
}*LinkStackNode;

typedef struct
{
    
	LinkStackNode top;//栈顶
	int count;//计数器
}*LinkStack;

bool InitStack(LinkStack s)//初始化
{
    
	if (!s)
		return false;
	s->top = (LinkStackNode)malloc(sizeof(StackNode));
	s->top = NULL;
	s->count = 0;
	return true;
}

bool Is_Empty(LinkStack s)//判空
{
    
	return s->count == 0;
}

bool ClearStack(LinkStack s)//清栈
{
    
	LinkStackNode p, q;
	p = s->top;
	while (p)
	{
    
		q = p;
		p = p->next;
		free(q);
	}
	s->count = 0;
	return true;
}

int GetLength(LinkStack s)//栈的数据个数
{
    
	return s->count;
}

T GetTop(LinkStack s)//获取栈顶元素
{
    
	if (s->top==NULL)
		return -1;
	return s->top->data;
}

bool Push(LinkStack s,T val)//入栈
{
    
	if (!s)
		return NULL;
	LinkStackNode p = (LinkStackNode)malloc(sizeof(LinkStackNode));
	p->data = val;
	p->next = s->top;
	s->top = p;
	s->count++;
	return true;
}

T Pop(LinkStack s)//出栈
{
    
	if (Is_Empty(s))
		return -1;
	T tmp = s->top->data;
	LinkStackNode p = s->top;
	s->top = s->top->next;
	//free(p);
	s->count--;
	return tmp;
}

void Show(LinkStack s)//遍历
{
    
	if (!s)
		return;
	LinkStackNode q = s->top;
	while (q)
	{
    
		printf("%d ", q->data);
		q = q->next;
	}
	printf("\n");
}

int main()
{
    
	LinkStack s = (LinkStack)malloc(sizeof(LinkStack));
	InitStack(s);
	for (int i = 1; i <= 5; i++)
	{
    
		Push(s, i);
	}
	printf("Len: %d\n", GetLength(s));
	Show(s);
	printf("%d\n", GetTop(s));
	printf("%d\n", Pop(s));
	Show(s);
	return 0;
}