Сортировка массива структур по одному полю - C (СИ)

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
 
typedef struct PERSON {
    char * name;
    int height;
    double weight;
}person_t;
 
int name_cmp(const void * a, const void *b){
    return strcmp(((person_t*)a)->name, ((person_t*)b)->name);
}
 
int height_cmp(const void * a, const void *b){
    return ((person_t*)a)->height - ((person_t*)b)->height;
}
 
int weight_cmp(const void * a, const void *b){
    double d = ((person_t*)a)->weight - ((person_t*)b)->weight;
    return ( d < 0.0 ) ? -1 : ( d > 0.0 ) ? 1 : 0;
}
 
#define NUM_PERSONS 3
 
int main(void){
    person_t persons[NUM_PERSONS] = {
        { .name = "Sidorov", .height = 173, .weight = 80.2 },
        { .name = "Petrov", .height = 182, .weight = 75.5 },
        { .name = "Ivanov", .height = 180, .weight = 99.9 }
    };
    int i;
    
    printf("\nUnsorted:\n");
    for ( i = 0; i < NUM_PERSONS; ++i )
        printf("%s\t%d\t%.1f\n", persons[i].name, persons[i].height, persons[i].weight);
    
    qsort(persons, NUM_PERSONS, sizeof(person_t), name_cmp);
    printf("\nSorted by name:\n");
    for ( i = 0; i < NUM_PERSONS; ++i )
        printf("%s\t%d\t%.1f\n", persons[i].name, persons[i].height, persons[i].weight);
        
    qsort(persons, NUM_PERSONS, sizeof(person_t), height_cmp);
    printf("\nSorted by height:\n");
    for ( i = 0; i < NUM_PERSONS; ++i )
        printf("%s\t%d\t%.1f\n", persons[i].name, persons[i].height, persons[i].weight);
    
    qsort(persons, NUM_PERSONS, sizeof(person_t), weight_cmp);
    printf("\nSorted by weight:\n");
    for ( i = 0; i < NUM_PERSONS; ++i )
        printf("%s\t%d\t%.1f\n", persons[i].name, persons[i].height, persons[i].weight);
        
    exit(0);
}