I am allitle confused about shell sorting , how exactly is it done ?

Say I have an array of 25 , 15 , 20 ,40,9,2,4,5,100,1

The next step would be gap1/2 , which would be 5 right ?

so then it...

nevermind finally got it :)

Ok ... nevermind ... don't got it ....

This is what I put

void Fraction::reduce()

{
int b=den;
int c;
int a=num;

nevermind got it finally

I've been working on this class for about 2-3 weeks and I got everything done except the reducing part. I can't figure it out , I know you have to use the GCD algorithm , but I cannot figure out how...