结构体的 Qsort 数组-解网

问：

我有一个结构数组，我要将条目添加到其中

typedef struct card
{
    char* name;
} card_t;

这些是文件中的名字：被妖精偷走、永恒隔离、尸体骑士、奥尔佐夫执法者

我有一个 qsort 函数，它应该按字母顺序对所有条目进行排序。但是，它不起作用。

// FUNCTION FOR QSORT()
int cmpname (const void *pa, const void *pb) {
    const card_t **p1 = pa;
    const card_t **p2 = pb;
    
    return strcmp((*p1(->name, (*p2)->name); 
}

#include "card.h"
#include <fcntl.h>
#include <stdlib.h>
#include <stdio.h>
#include <unistd.h>
#include <string.h>
// FUNCTION FOR QSORT()
int cmpname (const void *pa, const void *pb) {
    const card_t *p1 = pa;
    const card_t *p2 = pb;
    
    return strcmp(p1->name, p2->name); 
}

int main(int argc, char **argv) {   
    char *buf = NULL;
    size_t bufsiz = 0;
    FILE *input_file;
    
    if((input_file = fopen(argv[1], "r")))
    {
        ssize_t result = getline(&buf, &bufsiz, input_file);
        int num_entries = 1;
        card_t **cards = NULL;
    
        int i = 0;
        int cardsaccum = 0;
        int id;
        char *name_duplicate;

        // GETS LINE FROM THE CSV FILE
        result = getline(&buf, &bufsiz, input_file);
        // WHILE THE FILE STILL HAS TEXT
        while (result > 0)
        {   // COPIES BUFFER TO SAVE THE MEMORY ADDRESS
            char *stringp = buf;
            // ALLOCATES MEMORY
            cards = realloc(cards, sizeof(card_t *) * num_entries);
            cards[cardsaccum] = malloc(sizeof(card_t));
            
            cards[cardsaccum]->name = strsep(&stringp, "\"");
            
            cardsaccum++;
            num_entries++;
            // MUST NULL THE BUFFER BEFORE GETLINE 
            buf = NULL;
            // NEXT LINE
            result = getline(&buf, &bufsiz, input_file);
            if(result == -1)
            {
                qsort(cards, cardsaccum - 1, sizeof(student_t *), cmpname);
                //printf("AFTER QSORT \n");
                //printf("\n");
                for(i = 0; i < cardsaccum;i++)
                {
                    printf("%s", cards[i]->name);
                }
            }
        }
        
        for(i=0; i < cardsaccum;i++)
        {
            free(cards[i]);
        }
        free(cards);
        free(buf);
        fclose(input_file);
        return 0;
    }
    else
    {
        fprintf(stderr, "./parser: cannot open(%s%s%s): No such file or directory\n", "\"", argv[1], "\""); 
        return 1;
    }
}

我的输出是：

Corpse Knight
Eternal isolation
Stolen by the Fae
Orzhov Enforcer

如果我的 qsort 函数正确，那么应该切换 Fae 和 Orzhov Enforcer 的 Stolen by the Fae。任何建议将不胜感激。

数组 C 内存结构

// FUNCTION FOR QSORT()
int cmpname (const void *pa, const void *pb) {
    const card_t **p1 = pa;  // These are pointer to the elements, and since each
    const card_t **p2 = pb;  // element is a pointer then these becomes pointers to pointers
    
    return strcmp((*p1)->name, (*p2)->name);  // Remember to dereference the pointers
}

您还有其他一些问题，例如元素数参数实际上应该是数组中的元素数，而不是顶部索引。为什么使用元素大小？qsortsizeof(char *)

结构体的 Qsort 数组

Qsort array of structs

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