Java 实例 查找两个数字的 GCD

public class GCDExample1 {

    public static void main(String[] args) {

        //Lets take two numbers 55 and 121 and find their GCD
        int num1 = 55, num2 = 121, gcd = 1;

        /* loop is running from 1 to the smallest of both numbers
         * In this example the loop will run from 1 to 55 because 55
         * is the smaller number. All the numbers from 1 to 55 will be 
         * checked. A number that perfectly divides both numbers would
         * be stored in variable "gcd". By doing this, at the end, the 
         * variable gcd will have the largest number that divides both
         * numbers without remainder.
         */
        for(int i = 1; i <= num1 && i <= num2; i++)
        {
            if(num1%i==0 && num2%i==0)
                gcd = i;
        }

        System.out.printf("GCD of %d and %d is: %d", num1, num2, gcd);
    }

}

GCD of 55 and 121 is: 11

public class GCDExample2 {

    public static void main(String[] args) {

        int num1 = 55, num2 = 121;

        while (num1 != num2) {
            if(num1 > num2)
                num1 = num1 - num2;
            else
                num2 = num2 - num1;
        }

        System.out.printf("GCD of given numbers is: %d", num2);
    }

}

GCD of given numbers is: 11

import java.util.Scanner;
public class GCDExample3 {

    public static void main(String[] args) {

        int num1, num2;

        //Reading the input numbers
        Scanner scanner = new Scanner(System.in);
        System.out.print("Enter first number:");
        num1 = (int)scanner.nextInt();

        System.out.print("Enter second number:");
        num2 = (int)scanner.nextInt();

        //closing the scanner to avoid memory leaks
        scanner.close();
        while (num1 != num2) {
            if(num1 > num2)
                num1 = num1 - num2;
            else
                num2 = num2 - num1;
        }

        //displaying the result
        System.out.printf("GCD of given numbers is: %d", num2);
    }

}

Enter first number:30
Enter second number:250
GCD of given numbers is: 10