插入排序

#include <iostream>
#include <ctime>
void insert_sort(int a[],int length)
{
    for(int i=1;i<length;i++)
    {
        int key=a[i];
        int j=i-1;
        while(j>=0 && key<a[j] )
        {
            a[j+1]=a[j];
            j--;
        }
        a[j+1]=key;
    }
}
void inline GetData(int a[],int length)
{
    for(int i=0;i<length;i++)
        std::cout<<a[i]<<",";

}

int main(void)
{
    const int len=20;
    int a[len]={};
    srand((unsigned)time(0));
    for(int n=0;n<len;n++)
        a[n]=rand()%len;
    std::cout<<"before: ";
    GetData(a,len);
    std::cout<<std::endl<<"after: ";
    insert_sort(a,len);
    GetData(a,len);
    return 0;
}

递归方法：

void insert_sort(int a[],int length)
{
    if(length>1)
    {
        insert_sort(a,length-1);
        int tmp=a[length-1];
        int i=0;
        for(i=length-2;i>=0;--i)
        {
            if(tmp<a[i])
                a[i+1]=a[i];
            else
                break;
        }
        a[i+1]=tmp;

    }

}