在C中按字母顺序对文件中的结构排序

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

// 定义结构
struct Person {
    char name[50];
    int age;
};

// 比较函数，用于排序
int compare(const void* a, const void* b) {
    struct Person* personA = (struct Person*)a;
    struct Person* personB = (struct Person*)b;
    return strcmp(personA->name, personB->name);
}

int main() {
    FILE* file;
    struct Person people[100];
    int numPeople = 0;

    // 打开文件并读取结构数据
    file = fopen("data.txt", "rb");
    if (file == NULL) {
        printf("无法打开文件\n");
        return 1;
    }

    while (fread(&people[numPeople], sizeof(struct Person), 1, file) == 1) {
        numPeople++;
    }

    fclose(file);

    // 对结构进行排序
    qsort(people, numPeople, sizeof(struct Person), compare);

    // 写入排序后的结构数据
    file = fopen("sorted_data.txt", "wb");
    if (file == NULL) {
        printf("无法创建文件\n");
        return 1;
    }

    fwrite(people, sizeof(struct Person), numPeople, file);

    fclose(file);

    printf("排序完成\n");

    return 0;
}