java - 为什么编译器显示错误

Question

代码如下

class Hotel {
 public int bookings;
 public void book() {
    bookings++;
 }
}

public class Test extends Hotel{
 public void book() {
    bookings--;
 }

 public void book(int size) {
    book();
    super.book();
    bookings += size;
 }

 public static void main(String... args) {
   Hotel hotel = new Test();
   hotel.book(2);  // Compiler show error
    System.out.print(hotel.bookings);
 }        
}       

Erorr: method book in class javaapplication1.Hotel cannot be applied to given types;

required: no arguments

found: int

reason: actual and formal argument lists differ in length

为什么编译器会报错？正在应用方法重载/覆盖编译器的哪条规则？

我们将不胜感激!!!

Answer 1

hotel 是 Hotel 类型，没有 book(int) 方法。

如果您想调用book(int)，您需要将hotel 的类型更改(或转换)为Test

   Test hotel = new Test();
   hotel.book(2);  // No error