用C语言定义顺序栈、链栈，完成栈的基本操作：建立空栈、入栈、出栈、取栈顶元素、判断栈中元素个数、置空栈；

在C语言中，我们可以分别用数组（顺序存储）和链表（动态存储）的方式来定义栈。

**顺序栈（Array Stack）**:

#include <stdio.h>

#define MAX_SIZE 100
typedef int ElementType;
typedef struct {
    ElementType data[MAX_SIZE];
    int top; // 栈顶指针
} SeqStack;

// 初始化空栈
void initSeqStack(SeqStack* s) {
    s->top = -1;
}

// 入栈 (Push)
void push(SeqStack* s, ElementType e) {
    if (s->top == MAX_SIZE - 1) {
        printf("Stack overflow.\n");
    } else {
        s->data[++(s->top)] = e;
    }
}

// 出栈 (Pop)
ElementType pop(SeqStack* s) {
    if (s->top == -1) {
        printf("Stack underflow.\n");
        return 0; // 返回默认值，表示栈为空
    } else {
        return s->data[s->top--];
    }
}

// 取栈顶元素 (Top)
ElementType getTop(SeqStack* s) {
    if (s->top == -1) {
        printf("Stack is empty.\n");
        return 0; // 返回默认值，表示栈为空
    } else {
        return s->data[s->top];
    }
}

// 判断栈中元素个数 (IsEmpty)
int isEmpty(SeqStack* s) {
    return s->top == -1;
}

// 置空栈 (Clear)
void clearSeqStack(SeqStack* s) {
    s->top = -1;
}

**链栈（Linked Stack）**:

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

typedef struct Node {
    ElementType data;
    struct Node* next;
} StackNode;

typedef struct {
    StackNode* top;
} LinkStack;

// 初始化空链栈
void initLinkStack(LinkStack* s) {
    s->top = NULL;
}

// 入栈 (Push)
void pushLinkStack(LinkStack* s, ElementType e) {
    StackNode* newNode = (StackNode*)malloc(sizeof(StackNode));
    newNode->data = e;
    newNode->next = s->top;
    s->top = newNode;
}

// 出栈 (Pop)
ElementType popLinkStack(LinkStack* s) {
    if (s->top == NULL) {
        printf("Stack underflow.\n");
        return 0; // 返回默认值，表示栈为空
    } else {
        StackNode* temp = s->top;
        ElementType value = temp->data;
        s->top = temp->next;
        free(temp);
        return value;
    }
}

// 取栈顶元素 (Top)
ElementType getTopLinkStack(LinkStack* s) {
    if (s->top == NULL) {
        printf("Stack is empty.\n");
        return 0; --返回默认值，表示栈为空
    } else {
        return s->top->data;
    }
}

// 判断栈中元素个数 (IsEmpty)
int isEmptyLinkStack(LinkStack* s) {
    return s->top == NULL;
}

// 置空栈 (Clear)
void clearLinkStack(LinkStack* s) {
    while (s->top != NULL) {
        StackNode* temp = s->top;
        s->top = s->top->next;
        free(temp);
    }
    s->top = NULL;
}