使用回调实现对一组任意类型的对象做快速排序

来源：互联网发布：超少年密码之人工智能编辑：程序博客网时间：2024/06/06 08:47

qsort函数实现对一组任意类型对象的排序，调用者提供 findPos_t 回调函数，在回调函数中实现对特定类型元素位置的查找。

// qsort.h#ifndef QSORT_H#define QSORT_Htypedef int (*findPos_t)(void *a[], int left, int right);extern void qsort(void *a[], int left, int right, findPos_t findPos);#endif

// qsort.c#include "qsort.h"void qsort(void * a[], int left, int right, findPos_t findPos) {    int pos;    if(left < right) {        pos = findPos(a, left, right);        qsort(a, left, pos - 1, findPos);        qsort(a, pos + 1, right, findPos);    }    }

// qsortMain.c#include <stdio.h>#include "qsort.h"typedef struct {    const char *name;    int score;} student_t;int findPos(void * a[], int left, int right) {    int val = *(int *)a[left];    while(left < right) {            while(left < right && val <= *(int *)a[right]) {                        right --;                    }            *(int *)a[left] = *(int *)a[right];                while(left < right && val >= *(int *)a[left]) {                        left ++;                    }            *(int *)a[right] = *(int *)a[left];        }    *(int *)a[left] = val;    return left;}int findPos_student(void * a[], int left, int right) {    student_t val = *(student_t *)a[left];    while(left < right) {            while(left < right && val.score <= ((student_t *)a[right])->score) {                        right --;                    }            *(student_t *)a[left] = *(student_t *)a[right];                while(left < right && val.score >= (*(student_t *)a[left]).score) {                        left ++;                    }            *(student_t *)a[right] = *(student_t *)a[left];        }    *(student_t *)a[left] = val;    return left;}int main(void) {    int i;    int data[5] = {1, 7, 4, 2, 5};    int *pdata[5] = {&data[0], &data[1], &data[2], &data[3], &data[4]};    qsort((void **)pdata, 0, 5 - 1, findPos);    for(i = 0; i < 5; i ++) {        printf("%d ", data[i]);    }    putchar('\n');    student_t list[4] = {{"Tom", 68}, {"Jerry", 72}, {"Moby", 60}, {"Kirby", 89}};    student_t *plist[4] = {&list[0], &list[1], &list[2], &list[3]};    qsort((void **)plist, 0, 4 - 1, findPos_student);    for(i = 0; i < 4; i ++) {        printf("%s %d\n", list[i].name, list[i].score);    }    return 0;}

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