运算符：一元，二元，三元，逻辑

运算符：一元，二元，三元，逻辑

二元运算符

package com.base02;
                                               //运算符

public class Demo01 {
    public static void main(String[] args) {
        //二元运算符
         //Ctrl + D :复制当前行到下一行
        int a=10;
        int b=20;
        int C=25;
        int d=25;
        System. out . println(a+b);
        System.out . println(a-b);
        System. out . println(a*b);
        System.out. println(a/b);   //0   int 四舍五入
        System.out. println(a/ (double)b);

        System.out. println("=========================================");



        Long A = 123123123123123L;
        int B = 123;
        short c = 10;
        byte D =8;

        //取高级别数据类型
        System. out . println(A+B+c+D); //Long
        System. out . println(B+c+D); //Int
        System. out . println((c+D)); //Int
        System.out. println("=========================================");



    //关系运算符返回的结果:正确， 错误  布尔值
            int x=10;
            int y=20;
            int z=21;
            System. out . println(z%x);  //取余数，z/x  21/10  2..1
            System. out . println(x>y);
            System. out . println(x<y);
            System. out . println(x==y);
            System. out. println(x!=y);



    }

}

a++ ++a a-- --a

package com.base02;
                          //a++   ++a   a--   --a
public class Demo02 {
    public static void main(String[] args) {
    //++--自增，自减一元运算符
    int a = 3;

    int b = a++;     //执行完这行代码后，先给b赋值，再自增
        // a = a + 1;
    System.out.println(a);
        System.out. println("=========================================");

    //a = a+ 1;
    int c = ++a;//执行完这行代码前，先自增，再给b赋值
    System.out.println(a);
    System.out.println(b);
    System.out.println(c);
    System.out. println("=========================================");


    //幂运算2^32*2*2 = 8
        double pow = Math.pow(3,2);
        System.out.println(pow);

}
}

逻辑运算，位运算

package com.base02;
                                         //逻辑运算，位运算
public class Demo03 {
    public static void main(String[] args) {
        //与(and)&&   或(or)||     非（取反)!()
        boolean a = true;
        boolean b = false;

        System.out.println("a && b: "+(b&&a));//逻辑与运算:两个变量都为真，结果才为true
        System.out.println("a || b:"+(a||b));//逻辑或运算:两个变量有一个为真，则结果才为true
        System.out.println("! (a &8 b):"+!(a&&b));//如果是真，则变为假，如果是假则变为真

        //短路运算
        int c = 5;
        boolean d = (c<4)&&(c++ < 4);    //前面为假，后面就不算了，短路，直接整式为假
        System.out.println(d);
        System.out.println(c);
        System.out. println("=========================================");

                                  //位运算
        /*
        A= 0011 1100
        B =0000 1101
            ------------------
        A&B = 0000 1100
        A/B = 0011 1101
        A^B = 0011 0001
         ~B = 1111 0010
            2*8 = 16  2*2*2*2  效率极高! ! !
                    <<  *2   左移
                    >>  /2   右移
            0000 0000 0
            0000 0061 1
            6000 0016 2
            0000 0011 3
            0000 0100 4
            0000 1000 8
            0001 0080 16

        */
            System.out.println( 2<<3);
        System.out. println("=========================================");


        int A = 10;
        int B = 20;
        A+=B; //a = a+b
        A-=B; //a = a-b
        System.out.println(A);
        //字符串连接符    + , string
        System.out.println( ""+A+B);
        System.out.println( A+B+"");



        }
}

三元运算

package com.base02;

public class Demo04 {
                                //三元运算符
    public static void main(String[] args) {
        //x ? y : z      如果x==true，则结果为y，否则结果为z

        int score = 50;
        String type = score < 60 ? "不及格" : "及格";//必须掌握
        // if

        System.out.println(type);

    }
}