問題：兩個整數的最大公因數是同時整除二者的最大整數。

全部程式碼：

public class GreatestCommonDivisor {

  public static void main(String[] args) {
    // TODO Auto-generated method stub
    long divisor = greatestCommonDivisor(80, 25);
    System.out.println("Divisor: " + divisor);
  }

  public static long greatestCommonDivisor(long param1, long param2) {
    while (param2 != 0) {
      long rem = param1 % param2;
      param1 = param2;
      param2 = rem;
    }
    return param1;
  }
  
}
 

Divisor: 5