I don't know what you're talking about when you say you can't use *, it seems you have a problem with precision for some test, try a different data type.

Then why can I use / operator if i can`t use *?

@Chrono: ^ is bitwise xor in a lot of languages, but in some like Julia and Factor, it's exponent.
In C++, that's bitwise xor.

Then what about / operator?

AFAIK ^ is a bitwise operator (in C++), so they aren't the same thing.

I was hoping I found a nice site to do some programs and learn something in C++.
Turns out this page dont know that a*a and a^2 are the same things....
Disappointment