C++如何用链表实现栈

可以使用一个指针作为栈顶，将新元素插入到链表头，每次弹出时从头部删除。具体的实现方式可以参考以下代码：

typedef struct Node {
    int data;
    struct Node* next;
} Node;

typedef struct Stack {
    Node* top;
} Stack;

void push(Stack* s, int val) {
    Node* new_node = (Node*) malloc(sizeof(Node));
    new_node->data = val;
    new_node->next = s->top;
    s->top = new_node;
}

int pop(Stack* s) {
    if (s->top == NULL) {
        printf("Stack is empty\n");
        return -1;
    }
    Node* temp = s->top;
    int val = temp->data;
    s->top = s->top->next;
    free(temp);
    return val;
}

在主函数中，可以这样使用：

int main() {
    Stack s;
    s.top = NULL; // 初始化栈顶指针
    push(&s, 1);
    push(&s, 2);
    push(&s, 3);
    int val = pop(&s); // val = 3
    val = pop(&s); // val = 2
    val = pop(&s); // val = 1
    val = pop(&s); // 输出 "Stack is empty"，val = -1
    return 0;
}