运算符

算术运算符

+ - * / % ++ --

public class OperateDemo1 {
    public static void main(String[] args){
        int num1 = 12;
        int num2 = 5;
        System.out.println(num1 - num2); // 7
        System.out.println(num1 * num2); // 60
        System.out.println(num1 / num2); // 2
        System.out.println(num1 % num2); // 2
    }
}
**************  **************  ************** ************** ************** 
public class OperateDemo2 {
    public static void main(String[] args){
        int num1 = 12;
        int num2 = 5;
        int preNum = ++num1;
        int backNum = num2--;
        System.out.println("num1 = " + num1 + ", num2 = " + num2 + "; preNum = " + preNum + ", backNum = " + backNum);
    }
}
//运行结果：num1 = 13, num2 = 4; preNum = 13, backNum = 5
/*
    int preNum = ++num1;的分析过程
    num1 = num1 + 1; preNum = num1;
    
    int backNum = num2--;的分析过程
    int temp2 = num2; num2 = num2 - 1; backNum = temp2;
    waring: 赋值运算符的优先级较低
*/

比较运算符

>
<
<=
>= ==

public class OperateDemo3 {
    public static void main(String[] args){
        int num = 30;
        char c = 'A';
        System.out.println(num - c);
        System.out.println(num > c);
        System.out.println(num < c);
        System.out.println(num >= c);
        System.out.println(num == c);
    }
}
// -35 false true false false

逻辑运算符

& &&
| ||
^
!

public class OperateDemo4 {
    public static void main(String[] args){
        int num1 = 30, num2 = 100;
        char c = 'A';
        System.out.println(num1 < c || num1 > num2);
        System.out.println(num1 < c && num1 > num2);
        System.out.println(!(num1 < c || num1 > num2));
    }
}
// true false false

& （|）和 &&（||）的区别在于一个不短路，一个短路

public class OperateDemo5 {
    public static void main(String[] args){
        int num1 = 39, num2 = 40;
        System.out.println(num1 > num2 && ++num1 > num2);
        System.out.println("num1 = " + num1 + ", num2 = " + num2);
        System.out.println(num1 > num2 & ++num1 > num2);
        System.out.println("num1 = " + num1 + ", num2 = " + num2);
    }
}
/* 运行结果：
    false
    num1 = 39, num2 = 40
    false
    num1 = 40, num2 = 40
*/

位运算符

~ & | >>
>>> <<

public class OperateDemo6 {
    public static void main(String[] args){
        int a = 1, b = -1;
        System.out.println(a & b);
        System.out.println(a | b);
        System.out.println(~a);
        System.out.println(a >> 2);
        System.out.println(b >>> 2);
        System.out.println(b << 2);
    }
}
/* 运行结果：
   a补码： 00000000 00000000 00000000 00000001
   b原码： 10000000 00000000 00000000 00000001
    反码： 11111111 11111111 11111111 11111110
    补码： 11111111 11111111 11111111 11111111
   & 补码：00000000 00000000 00000000 00000001 => 1
   | 补码：11111111 11111111 11111111 11111111 => -1
   ~ 补码：11111111 11111111 11111111 11111110 => -2
   >>2  ： 0
   >>>2 :  大正数
   << 2 :  -4
*/

三元运算符和赋值运算符

返回布尔 ? 表达式1 ： 表达式2

public class OperateDemo7 {
    public static void main(String[] args){
        int age = 19;
        String str = age > 18 ? "要对自己的行为负责到底" : "deepin";
        System.out.println(str);
    }
}
//运行结果 ： 要对自己的行为负责到底

交换两个数的值几种方法

public class OperateDemo8 {
    public static void main(String[] args){
        int num1 = 100, num2 = 789;
        //第一种方法
        int temp = num1;
        num1 = num2;
        num2 = temp;
        //第二种方法
        int sum = num1 + num2;
        num1 = sum - num1;
        num2 = sum - num2;
        //第三种方法
        num1 = num1 ^ num2;
        num2 = num2 ^ num1;
        num1 = num2 ^ num1;
        //第N...
        System.out.println("num1 = " + num1 + ", num2 = " + num2);
    }
}
//运行结果 ： 要对自己的行为负责到底