预算符

基本运算符

package com.beijing.xiaowen.operator;

public class Demo01 {
    public static void main(String[] args) {
        int a = 10;
        int a1 = 20;
        int a2 = 30;
        int a3 = 40;

        System.out.println(a * a1);
        System.out.println(a / a1);//0
        System.out.println(a / (double)a1);//0.5 有小数的时候，记得用浮点型
        System.out.println(a2 + a1);
        System.out.println(a3 - a1);


        long z = 8979879L;
        short x = 33;
        byte c = 2;
        int v = 10;
        System.out.println(z+x+c+v);//结果为long
        System.out.println(x+c+v);//结果为int
        System.out.println(x+c);
    }
}

自增自减运算符

package com.beijing.xiaowen.operator;

public class Demo02 {
    public static void main(String[] args) {
        int a = 1;
        int b = a++;//执行完这行代码后，先给b赋值，再自增
        System.out.println(b);//1
        int c = ++a;//执行完这行代码前，先自增，再给c赋值
        System.out.println(c);//3
    }
}

初识math类

        //幂运算
        double pow = Math.pow(3, 2);
        System.out.println(pow);//9

位运算符

package com.beijing.xiaowen.operator;

public class Demo03 {
    public static void main(String[] args) {
        //  & | ^ ~ << >>

        /**
        *  A = 0011 1100
        *  B = 0000 1101
        *  A&B = 0000 1100
        *  A|B = 0011 1101
        *  A^B = 0011 0001
        *  ~B  = 1111 001199
         *
         *  2*8  2*2*2*2
         *
         *  << *2
         *  >> /2
        * */
        System.out.println(2<<3);//16 
    }
}

字符串连接符

package com.beijing.xiaowen.operator;

public class Demo04 {
    public static void main(String[] args) {
        int a = 10;
        int b = 10;
        System.out.println(a+=b);//a=a+b
        System.out.println(a-=b);//a=a-b

        //字符串拼接符
        System.out.println(""+a+b);//1010
        System.out.println(a+b+"");//30
    }
}

三元运算符

package com.beijing.xiaowen.operator;

public class Demo05 {
    public static void main(String[] args) {
        //? :
        //x ? y : z   x为true则为y，否则为z
        int a = 66;
        System.out.println(a>88?"啊哈":"嗯哼");
    }
}