选择法排序小探

一、参考代码

#include<stdio.h>
#include <stdlib.h>
/****************************************
**选择排序法对十个整数进行排序 ***
****************************************/
//n为数组长度；
void sort(int a[],int n)
{
    int temp,min;
    int i=0;
    for(;i<n;i++)
    {
        min=i; //先假设最小下标为i
        int j=i+1;
        for(;j<n;j++)
        if(a[j]<a[min])
            min=j; //对i之后的数进行扫描将最小的数赋予min
        if(min!=i)
        {
            temp=a[i];
            a[i]=a[min];
            a[min]=temp;
        } //判断min与i是否相等，若＝则说明原假设正确反之交换数值
        printf("No.%d,i=%d,min=%d\t",i+1,i,min);
        int k = 0;
        for(;k<10;k++)
        {
            if(k==i)
                printf(" [%d], ",a[k]);
            else
                printf(" %d, ",a[k]);
        }
        printf("\n");
    }
}

//用main函数验证
int main()
{
    system("clear");
    int a[10]={85,66,34,86,52,74,61,25,24,11};
    int i=0;
    printf("provide you with ten numbers:\n");
    for(;i<10;i++)
        printf("%d,",a[i]);
    printf("\n");
    printf("________________________________________________________________\n");
    sort(a,10);
    printf("After selection sort:\n");
    printf("________________________________________________________________\n");
    for(i=0;i<10;i++)
        printf("%d,",a[i]);
    printf("\n");
    return 0;
}

 

二、运行效果

provide you with ten numbers:
85,66,34,86,52,74,61,25,24,11,
________________________________________________________________
No.1,i=0,min=9 [11], 66, 34, 86, 52, 74, 61, 25, 24, 85,
No.2,i=1,min=8 11, [24], 34, 86, 52, 74, 61, 25, 66, 85,
No.3,i=2,min=7 11, 24, [25], 86, 52, 74, 61, 34, 66, 85,
No.4,i=3,min=7 11, 24, 25, [34], 52, 74, 61, 86, 66, 85,
No.5,i=4,min=4 11, 24, 25, 34, [52], 74, 61, 86, 66, 85,
No.6,i=5,min=6 11, 24, 25, 34, 52, [61], 74, 86, 66, 85,
No.7,i=6,min=8 11, 24, 25, 34, 52, 61, [66], 86, 74, 85,
No.8,i=7,min=8 11, 24, 25, 34, 52, 61, 66, [74], 86, 85,
No.9,i=8,min=9 11, 24, 25, 34, 52, 61, 66, 74, [85], 86,
No.10,i=9,min=9 11, 24, 25, 34, 52, 61, 66, 74, 85, [86],
After selection sort:
________________________________________________________________
11,24,25,34,52,61,66,74,85,86,
[root@localhost select_sort]#

 

三、一点分析

   选择法排序原理：一次选定数组中的每一个数，记下当前位置并假设它是从当前位置开始后面数中的最小数min=i，从这个数的下一个数开始扫描直到最后一个数，并记录下最小数的位置min，扫描结束后如果min不等于i，说明假设错误，则交换min与i位置上数