package operator;
//=====================
//Demo07
//=====================
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);

        //字符串连接符  + , String
        System.out.println(""+a+b);

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

package operator;
//=====================
//Demo08
//=====================
public class Demo08 {
    public static void main(String[] args) {
        //  x ? y : z
        //如果x==true, 则结果为y,否则为z

        int score =80;
        String type = score <60 ? "不及格": "及格";//必须掌握
        //  if
        System.out.println(type);
    }
}