exponentiation c++ code example

Example 1: exponents c++

pow(base, exponent); //must #include <cmath> to use pow()

example: 

#include <iostream>
#include <cmath> //must include this library

int main ()
{
  	int y; 
	int x =10; 
  	y = pow(x,2); // y = x^2
}

Example 2: java binary exponentiation

/**
* Calculate a^n in O(logn) time, instead of O(n) time with naive approach.
**/
public static long powerRecursive(int base, int exponent){
  if(exponent == 0) return 1;
  return (exponent % 2 == 0) ?
    powerRecursive(base, exponent / 2) * powerRecursive(base, exponent / 2)
    : base * powerRecursive(base, (exponent - 1) / 2) *
      powerRecursive(base, (exponent - 1) / 2);
}