C qsort 嵌套结构数组

Question

我正在尝试对结构记录数组进行排序。由于某种原因，核心转储不断发生。

当我尝试对整数或结构数组执行相同的操作时，它工作得非常好。然而，当我开始使用嵌套结构时，它开始核心转储。

当前输出是:

Before sorting
first last 0  
first last 1  
first last 2  
first last 3  
first last 4  
first last 5  

AFTER sorting  
Segmentation fault (core dumped)

编译器:Cygwin

typedef struct {
    char last[NAMESIZE]; /* last name (1 word) */
    char first[NAMESIZE]; /* first name (1 word) */
} name;

typedef struct {
    name name;
    int score; /* score (between 0 & 100 inclusive) */
} record;

int compare (const void * a, const void * b){
    const record *recordA = (record *)a;
    const record *recordB = (record *)b;
    printf("%d: %d", recordA->score, recordB->score);
    return ( recordB->score - recordA->score );
}

int main (){
    record ** list;
    int i;
    list=malloc(6*sizeof(record*));
    printf("Before sorting\n");
    for(i=0; i<6; i++){ 
        list[i]=malloc(sizeof(record));
        strcpy(list[i]->name.first,"first");
        strcpy(list[i]->name.last,"last");
        list[i]->score=i;   
    }
    for (i=0; i<6; i++){
        printf ("%s %s %d\n",list[i]->name.first, list[i]-    >name.last,list[i]->score);         
    }

    printf("AFTER sorting\n");
    qsort (list, 6, sizeof(record), compare);
    for (i=0; i<6; i++){
        printf ("%s %s %d\n",list[i]->name.first, list[i]- >name.last,list[i]->score);         
    }    
  return 0;
}

Answer 1

list 是一个由 6 个指向 record 的指针组成的数组:

list=malloc(6*sizeof(record*));

因此您需要将相同的大小传递给qsort。

qsort(列表, 6, sizeof(记录), 比较);

应该是

qsort (list, 6, sizeof(record*), compare);

或者更好

qsort (list, 6, sizeof(*list), compare);