JavaAlgorithms/Maths/GCD.java

package Maths;

/**
 * This is Euclid's algorithm which is used to find the greatest common denominator Overide function
 * name gcd
 *
 * @author Oskar Enmalm 3/10/17
 */
public class GCD {

  /**
   * get greatest common divisor
   *
   * @param num1 the first number
   * @param num2 the second number
   * @return gcd
   */
  public static int gcd(int num1, int num2) {
    if (num1 < 0 || num2 < 0) {
      throw new ArithmeticException();
    }

    if (num1 == 0 || num2 == 0) {
      return Math.abs(num1 - num2);
    }

    while (num1 % num2 != 0) {
      int remainder = num1 % num2;
      num1 = num2;
      num2 = remainder;
    }
    return num2;
  }

  /**
   * get greatest common divisor in array
   *
   * @param number contains number
   * @return gcd
   */
  public static int gcd(int[] number) {
    int result = number[0];
    for (int i = 1; i < number.length; i++)
      // call gcd function (input two value)
      result = gcd(result, number[i]);

    return result;
  }

  public static void main(String[] args) {
    int[] myIntArray = {4, 16, 32};

    // call gcd function (input array)
    System.out.println(gcd(myIntArray)); // => 4
    System.out.printf("gcd(40,24)=%d gcd(24,40)=%d%n", gcd(40, 24), gcd(24, 40)); // => 8
  }
}