Java自增和自减 逻辑运算符 位运算符

 

/* int b = 7;
        int c = b++;
        System.out.println(b);  //8
        System.out.println(c);  //8*/

        int a = 8;
        //int b = a++;
        int b = ++a;
        System.out.println(a);  //9  //9
        System.out.println(b);  //8  //9

        int c = 9;
       // int d = c--;
        int d = --c;
        System.out.println(c);  //8  //8
        System.out.println(d);  //9  //8

　　

 

 

 

 

        int a = 10;
        int b = 20;
        System.out.println(""+a+b);   //字符串如果在加号前面，后面的数会拼接
        System.out.println(a+b+"");   //字符串如果在加号后面，前面的数会运算