JavaAlgorithms/Maths/PowRecursion.java

package Maths;

public class PowRecursion {
  public static void main(String[] args) {
    assert Double.compare(pow(2, 0), Math.pow(2, 0)) == 0;
    assert Double.compare(pow(0, 2), Math.pow(0, 2)) == 0;
    assert Double.compare(pow(2, 10), Math.pow(2, 10)) == 0;
    assert Double.compare(pow(10, 2), Math.pow(10, 2)) == 0;
  }

  /**
   * Returns the value of the first argument raised to the power of the second argument
   *
   * @param a the base.
   * @param b the exponent.
   * @return the value {@code a}<sup>{@code b}</sup>.
   */
  public static long pow(int a, int b) {
    return b == 0 ? 1 : a * pow(a, b - 1);
  }
}