算法学习-求两个整数的最大公约数

package com.me.main;

import java.util.Scanner;

/**
 * 求最大公因数
 */
public class BigCommonFactor
{
    public static void main (String[] args)
    {
        Scanner scanner = new Scanner(System.in);
        System.out.println("please input first number: ");
        String s1 = scanner.nextLine();
        System.out.println("please input second number: ");
        String s2 = scanner.nextLine();
        int firstNumber  = 0 ;
        int secondNumber = 0 ;
        try
        {
            firstNumber = Integer.parseInt(s1);
            secondNumber = Integer.parseInt(s2);
        }
        catch (NumberFormatException e)
        {
            System.out.println("input have error : firstNumber = " + s1 + ", secondNumber = " + s2 );
            System.out.println(e);
            throw e;
        }

        int bigCommonFactor = getBigCommonFactor(firstNumber,secondNumber);

        System.out.println("the big common  factor is:" +  bigCommonFactor);
    }

    public  static int getBigCommonFactor(int n, int m)
    {
        if (m % n == 0)
        {
            return n;
        }

        int r = m % n;
        m = n;
        n = r;

        return getBigCommonFactor(n,m);
    }
}