习题——不需要额外空间(变量)，交换俩个数的值

交换

• 问题描述：现在有A和B俩个数，不能定义额外的变量，从而实现对A和B值的交换

• 例如：A = 3；B = 4；交换之后A = 4；B = 3；

• 代码实现：

1. 首先使用额为变量

import java.util.Scanner;
public class TestDemo1 {
    
    
    public static void main(String[] args) {
    
    
        Scanner scan = new Scanner(System.in);
        int A = scan.nextInt();
        int B = scan.nextInt();

        int tmp = A;
        A = B;
        B =tmp;
        System.out.println("A = "+A+" B = "+B);
    }
}    

2. 不使用额外变量

import java.util.Scanner;
public class TestDemo1 {
    
    
    public static void main(String[] args) {
    
    
        Scanner scan = new Scanner(System.in);
        int A = scan.nextInt();
        int B = scan.nextInt();

        A = A+B;
        B = A-B;
        A = A-B;
        System.out.println("A = "+A+" B = "+B);
    }
}