anyone would tell me what is shell sorting?What is "Knuth"order (以 3h+1 速度遞增)?

void Shell_sorting(int a[], int n)
{

int i, j, h, up;



for(h=1; h<=n/9; h=3*h+1)



for(; h>0; h=h/3)



for(i=h; i<n; i++)

{

up=a;

j=i;



while( j>=h && a[j-h]>up )

{

a[j]=a[j-h];

j=j-h;

}



a[j]=up;

}
}

Would anyone would explain how the three for-loops going on?
What are their purposes?

Very sorry that I am not learning C or C++ or Java...

But I am learning Pascal

樓主可以先參考一下Wikipedia有關的資料:
http://en.wikipedia.org/wiki/Shell_sort