How to write a function that can calculate power in Java. No loops

Question

I\'ve been trying to write a simple function in Java that can calculate a number to the nth power without using loops.
I then found the Math.pow(a, b) class...

Answer 1

Try with recursion:

int pow(int base, int power){
    if(power == 0) return 1;
    return base * pow(base, --power);
}

Answer 2

Function to handle +/- exponents with O(log(n)) complexity.

double power(double x, int n){
 if(n==0)
  return 1;

  if(n<0){
      x = 1.0/x;
      n = -n;
  }
 double ret = power(x,n/2);
 ret = ret * ret;
 if(n%2!=0)
   ret = ret * x;
 return ret;

}

Answer 3

Use this code.

public int mypow(int a, int e){
    if(e == 1) return a;
    return a * mypow(a,e-1);
}