描述

完成这个内部可以存储任意类型的双向循环链表的构建。你只需要补充相关函数。

链表结构

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

typedef void (*DeleteFunction)(void*);
typedef void (*PrintFunction)(void*);

struct DataNode {
    DeleteFunction delete_function;
    void* data;
    struct DataNode* next;
    struct DataNode* prev;
};

typedef struct DataNode* List;
typedef struct DataNode* Node;

List create_list();

void delete_node(List head, Node node);

void pop_front(List head);

void clear_list(List head);

void free_list(List head);

void push_front(List head, void* data, DeleteFunction delete_function);

void print_list(List head, PrintFunction print_function);

void print_float(void* data) {
    printf("%.2f ", *((float*)data));
}

float list_sum(List head) {
    if (head == NULL) return 0.0f;

    float sum = 0.0f;
    Node current = head->next;
    while (current != head) {
        sum += *((float*)current->data);
        current = current->next;
    }
    return sum;
}

int list_size(List head) {
    if (head == NULL) return 0;

    int count = 0;
    Node current = head->next;
    while (current != head) {
        count++;
        current = current->next;
    }
    return count;
}

int main() {
    List list = create_list();
    int n;
    char command[20];

    scanf("%d", &n);

    for (int i = 0; i < n; i++) {
        scanf("%s", command);

        if (strcmp(command, "PUSH") == 0) {
            float value;
            scanf("%f", &value);
            float* data = (float*)malloc(sizeof(float));
            *data = value;
            push_front(list, data, free);
            printf("PUSH %.2f OK\n", value);

        } else if (strcmp(command, "POP") == 0) {
            if (list_size(list) > 0) {
                float front_value = *((float*)list->next->data);
                pop_front(list);
                printf("POP %.2f OK\n", front_value);
            } else {
                printf("POP FAIL: list is empty\n");
            }

        } else if (strcmp(command, "PRINT") == 0) {
            if (list_size(list) > 0) {
                printf("LIST: ");
                print_list(list, print_float);
            } else {
                printf("LIST: empty\n");
            }

        } else if (strcmp(command, "SUM") == 0) {
            float sum = list_sum(list);
            printf("SUM: %.2f\n", sum);

        } else if (strcmp(command, "SIZE") == 0) {
            int size = list_size(list);
            printf("SIZE: %d\n", size);

        } else if (strcmp(command, "CLEAR") == 0) {
            clear_list(list);
            printf("CLEAR OK\n");

        } else {
            printf("ERROR: unknown command %s\n", command);
        }
    }

    free_list(list);
    return 0;
}


// 你的代码会被附加到这里

函数列表

这些是你需要补充的函数，你也只需提交这些函数部分：

List create_list();

void delete_node(List head, Node node);

void pop_front(List head);

void clear_list(List head);

void free_list(List head);

void push_front(List head, void* data, DeleteFunction delete_function);

void print_list(List head, PrintFunction print_function);

Samples

10
PUSH 1.5
PUSH 2.5
PUSH 3.5
PRINT
SUM
SIZE
POP
PRINT
SUM
SIZE

PUSH 1.50 OK
PUSH 2.50 OK
PUSH 3.50 OK
LIST: 3.50 2.50 1.50 
SUM: 7.50
SIZE: 3
POP 3.50 OK
LIST: 2.50 1.50 
SUM: 4.00
SIZE: 2