将子类分配给每个数组元素（运行时类型）

Question

I have a base class Building and subclasses House and School . I have declared an array of Building objects the following way. I am not sure how to assign subclasses to each array element (run time type).

Building[] House = new Building[3];
Building[] School = new School[2];

Answer 1

You can use instanceof to determine the subclass

if (building instanceof House) {
    House[0] = building;
}

Answer 2

I'm not sure if you are asking how to check types at runtime or to populate with types at runtime. If the latter then see @Salah's answer using instanceof . In particular, why the House array is being populated with Building objects while the School array is being populated with School objects is confusing me.

To assign:

Building[] house = new House[3];
Building[] school = new School[2];

You could also populate the array with Building objects and then use type checking when you need to down the road.