求解C语言（结构和链表）

Question

查找书籍：用链表输入4本书的名称、作者、定价，并存入结构数组中,从中查找定价最高和最低的书的名称、作者、定价并输出。试编写程序。

Answer 1

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

// 定义书籍结构体
struct Book {
    char title[100];
    char author[100];
    float price;
    struct Book* next;
};

// 函数声明
void addBook(struct Book** head, const char* title, const char* author, float price);
void findMinMaxPrice(struct Book* head, struct Book** maxBook, struct Book** minBook);
void printBookInfo(const char* label, struct Book* book);

int main() {
    struct Book* head = NULL;

    // 输入4本书的信息
    for (int i = 0; i < 4; ++i) {
        char title[100], author[100];
        float price;

        printf("请输入第%d本书的信息：\n", i + 1);
        printf("书名: ");
        scanf("%s", title);
        printf("作者: ");
        scanf("%s", author);
        printf("定价: ");
        scanf("%f", &price);

        addBook(&head, title, author, price);
    }

    // 查找定价最高和最低的书
    struct Book* maxBook = NULL;
    struct Book* minBook = NULL;
    findMinMaxPrice(head, &maxBook, &minBook);

    // 输出结果
    printf("\n定价最高的书:\n");
    printBookInfo("书名", maxBook);
    printBookInfo("作者", maxBook);
    printBookInfo("定价", maxBook);

    printf("\n定价最低的书:\n");
    printBookInfo("书名", minBook);
    printBookInfo("作者", minBook);
    printBookInfo("定价", minBook);

    // 释放链表内存
    struct Book* current = head;
    while (current != NULL) {
        struct Book* next = current->next;
        free(current);
        current = next;
    }

    return 0;
}

// 添加书籍到链表
void addBook(struct Book** head, const char* title, const char* author, float price) {
    struct Book* newBook = (struct Book*)malloc(sizeof(struct Book));
    strcpy(newBook->title, title);
    strcpy(newBook->author, author);
    newBook->price = price;
    newBook->next = *head;
    *head = newBook;
}

// 查找定价最高和最低的书
void findMinMaxPrice(struct Book* head, struct Book** maxBook, struct Book** minBook) {
    struct Book* current = head;

    if (current == NULL) {
        return; // 空链表
    }

    *maxBook = current;
    *minBook = current;

    while (current != NULL) {
        if (current->price > (*maxBook)->price) {
            *maxBook = current;
        }
        if (current->price < (*minBook)->price) {
            *minBook = current;
        }
        current = current->next;
    }
}

// 输出书籍信息
void printBookInfo(const char* label, struct Book* book) {
    printf("%s: %s\n", label, (label == "书名") ? book->title : ((label == "作者") ? book->author : ""));
    if (label == "定价") {
        printf("%.2f\n", book->price);
    }
}