Java交换变量

int num1 = 10;
int num2 = 20;
int num1 = 10;
int num2 = 20;
int num1 = 10;
int num2 = 20;

已知num1=10，num2=20，让他们的值转换。

简单，实用，方法一

采用一个临时变量先储存其中一个值。

int temp = num1;
    num1 = num2;
    num2 = num1;
    System.out.println("num1="+num1+"num2="+num2);
int temp = num1;
    num1 = num2;
    num2 = num1;
    System.out.println("num1="+num1+"num2="+num2);
int temp = num1;
		num1 = num2;
		num2 = num1;
		System.out.println("num1="+num1+"num2="+num2);

方法二

num1 = num1 + num2;
    num2 = num1 - num2;
    num1 = num1 - num2;
    System.out.println("nun1="+num1+"num2="+num2);
num1 = num1 + num2;
    num2 = num1 - num2;
    num1 = num1 - num2;
    System.out.println("nun1="+num1+"num2="+num2);
num1 = num1 + num2;
		num2 = num1 - num2;
		num1 = num1 - num2;
		System.out.println("nun1="+num1+"num2="+num2);

优点：不需要新建一个变量，节省内测

弊端：①相加操作肯超出储存范围②有局限性（数值类型）

方法三

num1 = num1 ^ num2;
    num2 = num1 ^ num2;
    num1 = num1 ^ num2;
    System.out.println("num1="+num1+"num2="+num2);
num1 = num1 ^ num2;
    num2 = num1 ^ num2;
    num1 = num1 ^ num2;
    System.out.println("num1="+num1+"num2="+num2);
num1 = num1 ^ num2;
		num2 = num1 ^ num2;
		num1 = num1 ^ num2;
		System.out.println("num1="+num1+"num2="+num2);

转为二进制，相同二进制进行^运算，1^1=0,0^0=0

不同二进制运算1^0=1,0^1=1

弊端：有局限性（数值类型）