在C中对名称和id进行排序

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

// 定义一个结构体存储名称和id
typedef struct {
    char name[100];
    int id;
} Person;

// 按照id升序进行排序的比较函数
int compareById(const void *a, const void *b) {
    const Person *p1 = (const Person *)a;
    const Person *p2 = (const Person *)b;
    
    return p1->id - p2->id;
}

// 按照名称字典序进行排序的比较函数
int compareByName(const void *a, const void *b) {
    const Person *p1 = (const Person *)a;
    const Person *p2 = (const Person *)b;
    
    return strcmp(p1->name, p2->name);
}

int main() {
    int i;
    
    // 初始化一些Person对象
    Person people[] = {
        {"John", 3},
        {"Alice", 2},
        {"Bob", 1}
    };
    int count = sizeof(people) / sizeof(Person);
    
    printf("排序前的顺序：\n");
    for (i = 0; i < count; i++) {
        printf("%s %d\n", people[i].name, people[i].id);
    }
    
    // 按照id进行排序
    qsort(people, count, sizeof(Person), compareById);
    
    printf("\n按照id升序排序后的顺序：\n");
    for (i = 0; i < count; i++) {
        printf("%s %d\n", people[i].name, people[i].id);
    }
    
    // 按照名称进行排序
    qsort(people, count, sizeof(Person), compareByName);
    
    printf("\n按照名称字典序排序后的顺序：\n");
    for (i = 0; i < count; i++) {
        printf("%s %d\n", people[i].name, people[i].id);
    }
    
    return 0;
}