instanceof操作符判断对象类型

　　

　　instanceof 的语法格式如下：

myobject instanceof ExampleClass

myobject：某类的对象引用

ExampleClass：某个类

class Quadrangle{
    public static void draw(Quadrangle q) {
    }
}

class Square extends Quadrangle {
    
}

class Anything {
    
}
public class Parallelogram extends Quadrangle {

    public static void main(String[] args) {

        Quadrangle q = new Quadrangle();
        //判断父类对象是否为Parallelogram子类的一个实例
        if(q instanceof Parallelogram) {
            Parallelogram p = (Parallelogram) q;
        }
        if(q instanceof Square){
            Square s = (Square)q;
        }
    }

}