How to make a recursion power function witch allows you to use fractions as the power ?

Question

for exemple when I have 3 to the 1/3 power.

My function:
template <class T,class U>
U power(T x,U y)
{
if(y==0) return 1;
else return x * power(x,y-1); // works only when y=int
}

Answer 1

Here's what happens:

Let's say you make y a float with the value 1/3 = 0.333

The second time the template runs, y is now a negative value, and it will keep running and keep subtracting 1 from y, so you will never hit 0 with a fractional/decimal value.

Instead change y==0 to y<=0 and it should work, I just tested it.

Answer 2

My output is the same as the x number. I don't know why.

//edit
Outputs:
27^0.333=27
27^0.5=27
2^1.5=4
2^2.5=8

Doesn't work, It's rounding up y ?