基于双向链表实现的C语言栈无输出问题排查求助

问题核心是函数参数采用值传递，所有操作栈的函数（push、pop等）修改的都是栈结构体的副本，而非main函数中定义的原栈。原栈s1始终处于初始化的空状态，所以print_s遍历不到任何节点，自然无输出。

具体修改方案 #

将所有操作栈的函数参数改为指针传递，确保函数内的修改作用于原栈：

1. 修改push函数（新增内存分配失败判断）：

void push(Stack *s, int elm) {
    Node* updated_head = create_node(elm);
    if (!updated_head) return;
    if (!s->head) {
        s->head = updated_head;
        s->tail = s->head;
    } else {
        updated_head->next = s->head;
        s->head->prev = updated_head;
        s->head = updated_head;
    }
    s->size++;
    s->top = s->head->data;
}

2. 修改pop函数（新增空栈判断，避免空指针访问）：

int pop(Stack *s) {
    if (is_empty_s(*s)) {
        fprintf(stderr, "栈为空，无法执行pop操作\n");
        exit(EXIT_FAILURE);
    }
    Node* node = s->head;
    int elm = node->data;
    s->head = s->head->next;
    if (s->head) {
        s->head->prev = NULL;
        s->top = s->head->data;
    } else {
        s->tail = NULL;
        s->top = -1;
    }
    s->size--;
    free(node);
    return elm;
}

3. 修改top函数（新增空栈判断）：

int top(Stack *s) {
    if (is_empty_s(*s)) {
        fprintf(stderr, "栈为空，无法获取top值\n");
        exit(EXIT_FAILURE);
    }
    return s->top;
}

4. 修改clear_s函数：

void clear_s(Stack *s) {
    while (!is_empty_s(*s))
        pop(s);
}

5. 修改reverse_s函数（改为直接修改原栈，无需返回值）：

void reverse_s(Stack *s) {
    Stack s2 = stack_init;
    while (!is_empty_s(*s)) {
        push(&s2, pop(s));
    }
    *s = s2;
}

6. 修改main函数中的调用方式：

int main() {
    Stack s1 = stack_init;
    push(&s1, 5);
    push(&s1, 4);
    push(&s1, 3);
    push(&s1, 2);
    push(&s1, 1);
    print_s(s1); // print_s仅读取栈内容，值传递即可
    
    // 可选测试反转功能
    reverse_s(&s1);
    printf("反转后：");
    print_s(s1);
    
    clear_s(&s1);
    return 0;
}

修正后的完整代码 #

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

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

typedef struct Stack {
    int size;
    Node* head;
    Node* tail;
    int top;
} Stack;

const Stack stack_init = { .size = 0, .head = NULL, .tail = NULL, .top = -1 };

Node* create_node(int elm) {
    Node* node = malloc(sizeof * node);
    if (!node) return node;
    node->data = elm;
    node->prev = NULL;
    node->next = NULL;
    return node;
}

void push(Stack *s, int elm) {
    Node* updated_head = create_node(elm);
    if (!updated_head) return;
    if (!s->head) {
        s->head = updated_head;
        s->tail = s->head;
    } else {
        updated_head->next = s->head;
        s->head->prev = updated_head;
        s->head = updated_head;
    }
    s->size++;
    s->top = s->head->data;
}

int pop(Stack *s) {
    if (is_empty_s(*s)) {
        fprintf(stderr, "栈为空，无法执行pop操作\n");
        exit(EXIT_FAILURE);
    }
    Node* node = s->head;
    int elm = node->data;
    s->head = s->head->next;
    if (s->head) {
        s->head->prev = NULL;
        s->top = s->head->data;
    } else {
        s->tail = NULL;
        s->top = -1;
    }
    s->size--;
    free(node);
    return elm;
}

int top(Stack *s) {
    if (is_empty_s(*s)) {
        fprintf(stderr, "栈为空，无法获取top值\n");
        exit(EXIT_FAILURE);
    }
    return s->top;
}

void clear_s(Stack *s) {
    while (!is_empty_s(*s))
        pop(s);
}

void reverse_s(Stack *s) {
    Stack s2 = stack_init;
    while (!is_empty_s(*s)) {
        push(&s2, pop(s));
    }
    *s = s2;
}

int is_empty_s(Stack s) {
    return s.tail == NULL;
}

void print_s(Stack s) {
    Node* trav = s.head;
    while (trav) {
        printf("%d ", trav->data);
        trav = trav->next;
    }
    printf("\n");
}

int main() {
    Stack s1 = stack_init;
    push(&s1, 5);
    push(&s1, 4);
    push(&s1, 3);
    push(&s1, 2);
    push(&s1, 1);
    print_s(s1);
    
    reverse_s(&s1);
    printf("反转后：");
    print_s(s1);
    
    clear_s(&s1);
    return 0;
}

运行后会输出：

1 2 3 4 5 
反转后：5 4 3 2 1 

内容的提问来源于stack exchange，提问作者v_head