链头 == 栈顶。

#include<iostream>
using namespace std;
// 链栈
typedef int ElemType;
typedef struct Linknode {ElemType data;struct Linknode *next;
} *LiStack;
// 初始化
void InitLiStack(LiStack &S) {S = (LiStack)malloc(sizeof(struct Linknode));S->next = NULL;
}
// 入栈
bool PushLiStack(LiStack &S, ElemType x) {LiStack p = (LiStack)malloc(sizeof(struct Linknode));p->data = x;p->next = S->next;S->next = p;return true;
}
// 出栈
bool PopLiStack(LiStack &S, ElemType &x) {if (S->next == NULL) return false;LiStack p = S->next;x = p->data;S->next = p->next;free(p);return true;
}
// 遍历
void TraverseLiStack(LiStack S) {LiStack p = S->next;while (p != NULL) {cout << p->data << " ";p = p->next;}cout << endl;
}
// 求链栈长度
int StackLength(LiStack S) {int length = 0;LiStack p = S->next;while (p != NULL) {length++;p = p->next;}return length;
}
int main() {LiStack S;ElemType x;InitLiStack(S);PushLiStack(S, 1);PushLiStack(S, 2);PushLiStack(S, 3);PopLiStack(S, x);cout << "出栈元素：" << x << endl;TraverseLiStack(S);cout << "链栈长度：" << StackLength(S) << endl;return 0;
}