JAVA学习（运算符二）

Posted 2020-12-05 黑客的黑

package operator;
//逻辑运算符 && （与）、||（或）、！（非）
public class Demo05 {
    public static void main(String[] args) {
        boolean a = true;
        boolean b = false;
        System.out.println("a && b:"+(a&&b));
        System.out.println("a || b:"+(a||b));
        System.out.println("!(a && b):"+!(a&&b));
        //短路运算
        int c = 5;
        boolean d = (c<4)&&(c++<4);
        System.out.println(d);//false
        System.out.println(c);//5
    }
}

package operator;

public class Demo06 {
    public static void main(String[] args) {

        System.out.println();
        /*
        A = 0011 1100
        B = 0000 1101

        A&B 0000 1100
        A/B 0011 1101
        A^B 0011 0001  相同取0，不同得1
        ~A  1100 0011  取反

        2*8 怎么运算最快？
        <<  *2
        >>  /2
         */
        System.out.println(2<<3);
    }
}

package operator;

public class Demo07 {
    public static void main(String[] args) {
        int a = 10;
        int b = 20;
        a+=b; //a=a+b
        a-=b; //a=a-b
        System.out.println(a);//10

        //字符串连接符  +
        System.out.println(a+b); //30
        System.out.println(""+a+b); //1020 只要不在最末尾，都会把其余转化为String
        System.out.println(a+b+""); //30
    }
}

package operator;

//三元运算符
public class Demo8 {
    public static void main(String[] args) {
        // x?y:z
        //x ture 结果为y，否则结果为z
        int score = 80;
        String type = score < 60 ?"不及格":"及格"; //必须掌握

        System.out.println(type);
    }
}