标题：strcmp_for_qsort和挂羊头卖狗肉的qsort
出处：Felix021
时间：Mon, 28 Jun 2010 22:14:54 +0000
作者：felix021
地址：https://www.felix021.com/blog/read.php?1888

内容：
对字符指针数组使用qsort排序时，strcmp强制类型转换后不能直接用于qsort, 需要进一步的纠结的。包装……
p.s. 对于字符串数组char a[100][100]; 就可以用strcmp。
#include <stdio.h>
#include <stdlib.h>
#include <string.h>

typedef int (*cmp_func)(const void *, const void *);

int strcmp_for_qsort(const void *a, const void *b)
{
    char *x = *(char **)a, *y = *(char **)b;
    return strcmp(x, y);
}

void quicksort(void *p, int num, unsigned size, cmp_func cmp)
{
    int i, j;
    char *pos, *t = (char *) malloc(size);
    if (t == NULL) exit(1);
    for (i = 0; i < num; i++)
    {
        for (j = 0, pos = (char *)p; j < num - 1; j++, pos += size)
        {
            if (cmp(pos, pos + size) > 0)
            {
                memcpy(t, pos, size);
                memcpy(pos, pos + size, size);
                memcpy(pos + size, t, size);
            }
        }
    }
    free(t);
}

int main()
{
    char *pos[5] = {"a", "c", "e", "b", "d"};
    //qsort(pos, 5, sizeof(pos[0]), strcmp_for_qsort); // in stdlib
    quicksort(pos, 5, sizeof(pos[0]), strcmp_for_qsort); //fake
    for (int i = 0; i < 5; i++)
        puts(pos[i]);
    return 0;
}



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