# H面试程序（16）： 简单选择排序

`#include<stdio.h>#include<assert.h>void display(int * a, int n) {   assert(a);for(int i = 0; i < n; i++){printf("%d,",a[i]);}printf("\n");}void swap(int * a, int * b){   assert(a);assert(b);int temp;temp = *a;*a = *b;*b = temp;}void select_sort(int * a, int n){  assert(a);int i, j,min;for( i = 0; i < n-1  ; i++) //i 0 ~ n-2{min = a[i]; //每次选择一个作为最小值for( j = i; j < n; j++) // j i ~ n-1{if(a[j] < min){   swap(&(a[j]), &(a[i]));  }}}}int main(){   int a[10] ={2, 1, 3, 4, 5, 7,2,3, 6, 1};int num = sizeof(a)/sizeof(int);printf("before_sort:");display(a, num);select_sort(a,num);printf("after_sort:");display(a, num);return 0;}`

`#include <stdio.h>#include <time.h>//交换两个数据void swap(int *a, int *b){int temp;temp = *a;*a = *b;*b = temp;}//显示交换后的数组void display_array( int a[], int n ){    int i;    for( i = 0; i < n; i++ )        printf( "%d ", a[i] );}//选择排序void select_sort( int a[], int n ){int i ,j;for(i = 0; i<n-1 ; i++ )    {                                      int min = a[i];     //每次都设定最小的数，i 0 ~ 8for(j =i+1; j <n; j++)  // 将a[i]~ a[9]的数于当前最小的数进行比较，如果小于当前最小数就交换{if(a[j] < min){swap(&(a[j]), &(a[i]));}}}}int main(){clock_t start, finish;start = clock();    int  n = 10;    int a[] = { 2, 1, 3, 4, 5, 7, 6, 8 ,2,4};    printf( "Before sorting: " );    display_array( a, n );        select_sort( a, n );    printf( "After sorting: " );    display_array( a, n );    finish = clock();    printf("\n本次计算一共耗时: %f秒\n\n", (double)(finish-start)/CLOCKS_PER_SEC);    return 0;}`