库函数qsort的实现

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实现全能的qsort，既能实现结构体排序，又能排int，double，等等

错误的原因是没有考虑到自己定义的cmp函数的返回值是0 和1

main.c

#include "qsort.h"int cmp(const void *p1, const void *p2){return *(int *)p1 < *(int *)p2;}void show(int size,int a[]){    int  i = 0;for(i = 0; i < size; ++i){   printf("%d ",a[i]);}printf("\n");}int main(void){  int a[] = {20,3,1,4,5,6,7,9,8,0};int size = sizeof(a) / sizeof(a[0]);show(size, a);myqsort(a,size,sizeof(a[0]),cmp);    show(size, a);//printf("%d %d %d\n",a[0],a[1],a[2]);return 0;}

qsort.c

/*#include "qsort.h"void hqsort(void *base,size_t left,size_t right,int size,int (*compar)(const void *, const void *)){           size_t mid = (left + right) / 2;   size_t p = mid;   void* pivot = malloc(size);   memcpy(pivot, base + size * mid, size);           size_t i = left,j = right;           while (i < j){ for (; !(i >= p || compar(pivot, base + i * size) > 0); ++i);  // 在这里用<0的判断纠结了半天 if (i < p){memcpy(base + p * size, base + i * size, size);p = i;} for (; !(j <= p || compar( base + j * size , pivot) < 0); --j);                     if (j > p){memcpy(base + p * size, base + j * size, size);p = j;}                  //printf("i = %u j = %u\n",i,j); }memcpy(base + p * size, pivot,size);    free(pivot);    pivot = NULL;                if(p - left > 1){    hqsort(base, left, p - 1, size, compar);    }                if(right - p > 1){    hqsort(base, p + 1,right, size, compar);    }}void qsort(void *base, size_t nmemb, size_t size, int(*compar)(const void *, const void *)){         hqsort(base, 0, nmemb - 1,size,compar); }*/#include <stdlib.h>#include <stdio.h>#include <string.h>#include "qsort.h"void quick_sort (void* base, size_t left,size_t right, size_t size,int (*compar) (const void*, const void*)) {size_t p = (left + right) / 2;void* pivot = malloc (size);memcpy (pivot, base + p * size, size);size_t i = left, j = right;while (i < j) {for (; ! (i >= p ||compar (pivot,base + i * size) == 1); ++i);//printf("%d %d %d\n",*(int *)pivot,*(int *)(base + i * size),compar (pivot,//base + i * size) );if (i < p) {//printf("%d %d\n",*(int *)(base+p*size),*(int *)(base+i*size));memcpy (base + p * size,base + i * size, size);p = i;}for (; ! (j <= p || compar (base + j * size,pivot) == 1); --j);//printf("%d %d %d\n",*(int *)pivot,*(int *)(base + j * size),compar (pivot,//base + j * size) );if (j > p) {memcpy (base + p * size,base + j * size, size);p = j;}}memcpy (base + p * size, pivot, size);free (pivot);/*int k = 0;for (k = 0;k < 10;k++){    printf("%d ",*(int *)(base + k * size) );}printf("\n");*/pivot = NULL;if (p - left > 1)quick_sort (base, left, p - 1, size,compar);if (right - p > 1)quick_sort (base, p + 1, right, size,compar);}void myqsort (void* base, size_t nmemb,size_t size, int (*compar) (const void*,const void*)) {quick_sort (base, 0, nmemb - 1, size, compar);}

qsort.h

#ifndef __QSORT_H__#define __QSORT_H__#include <stdlib.h>#include <stdio.h>#include <string.h>void myqsort(void *, size_t, size_t, int(*)(const void *,const void *));#endif

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