运算符

运算符

自增自减

public class Demo02 {
    public static void main(String[] args) {
        int a = 3;
        int b = a++;
        // a = a + 1
        // a = a + 1
        int c = ++a;

        System.out.println(a); //5
        System.out.println(b); //3
        System.out.println(c); //5
    }
}

逻辑运算

public class Demo03 {
    public static void main(String[] args) {
        boolean a = true;
        boolean b = false;

        System.out.println(a&&b);  //false
        System.out.println(a||b); //true
        System.out.println(!(a&&b)); //true


        
    }
}

位运算

A = 0011 1100
B = 0000 1101      
A&B :  0000 1100
A|B :  0011 1101
A^B :  0011 0001 (相同为0， 不相同为1)
~B  :  1111 0010 (取反)

public class Demo03 {
    public static void main(String[] args) {
        // 位运算
        /*
          
          --------------------------
          2*8 = 16 怎么算最快？
          << :    *2
          >> :    /2
          效率高
          2:  0000 0010
          16: 0001 0000

          */
        System.out.println(2<<3); //16
    }
}

拓展

public class Demo04 {
    public static void main(String[] args) {
        int a = 10;
        int b = 20;

        System.out.println(""+a+b); //1020
        System.out.println(a+b+""); //30
    }
}