堆栈的链式存储实现

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

#define ElementType int
//堆栈的链式存储的单个节点
struct SNode {
	ElementType Data;
	struct SNode* Next;
};
typedef struct SNode* Stack;
//创建空的堆栈
Stack CreateStack()
{
	Stack s = (Stack)malloc(sizeof(struct SNode));
	s->Next = nullptr;
	return s;
}
//非空为0，空为1
bool IsEmpty(Stack s)
{
	return s->Next == nullptr ? true : false;
}
//虚拟头节点.
void Push(ElementType item, Stack s)
{
	//将元素压入堆栈
	Stack node = (Stack)malloc(sizeof(struct SNode));
	node->Data = item;
	node->Next = s->Next;
	s->Next = node;	
}
ElementType Pop(Stack s)
{
	//删除并返回栈顶元素
	if (IsEmpty(s)) {
		printf("stack is empty\n");
		return NULL;
	}
	Stack node = s->Next;
	ElementType value = node->Data;
	s->Next = node->Next;
	free(node);
	return value;
}

//测试程序
int main()
{
	Stack s = CreateStack();
	bool status;
	status = IsEmpty(s);
	if (status) {
		printf("栈为空\n");
	}
	else {
		printf("栈非空\n");
	}
	//插入一个元素10；
	Push(10, s);
	Push(20, s);
	ElementType value = Pop(s);
	printf("栈顶元素=%d\n", value);
	value = Pop(s);
	printf("栈顶元素=%d\n", value);
}