运算符3

public class Demo07 {
    public static void main(String[] args) {
        int a = 10;
        int b = 20;

        a += b;
        a -= b;

        System.out.println(a);

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

    }
}

//三元运算符
public class Demo08 {
    public static void main(String[] args) {
        // x ? y : z
        //如果X == true 则结果为y 否则结果为z

        int score = 50;
        String type = score < 60 ? "不及格" : "及格";//必须掌握 代码精简
        System.out.println(type);


    }
}