Lesson 3 上机练习题——继承

package bzu.aa;

public class Vehicle {
	
	int capacity;
	Vehicle()
	{
		capacity=2;
		System.out.println("执行交通工具类的无参构造方法");
	}
	Vehicle(int capacity )
	{
		this.capacity = capacity;
		System.out.println("执行交通工具的有参构造方法。");
	}
	public int getCapacity() {
		return capacity;
	}
	public void setCapacity(int capacity) {
		this.capacity = capacity;
	}
	
	void print()
	{
		System.out.println("[Vehicle]---capacity:"+capacity);
	}

}

package bzu.aa;

public class Car extends Vehicle{
	protected int speed;
	public Car()
	{
		super();
		speed =0;
		System.out.println("执行汽车类的无参构造方法。");
	}
	Car(int speed)
	{
		super();
		this.speed = speed;
		System.out.println("执行汽车类的有参构造方法。");
	}
	public int speedup()
	{
		speed+=10;
		return speed;
	}
	
	public int speeddown()
	{
		speed-=15;
		return speed;
	}
	public void print()
	{
		super.print();
		System.out.println("[Car]---speed:"+speed+",capacity:"+capacity);
	}

}

package bzu.bb;

import bzu.aa.Car;

public final class Bus extends Car{
	int capacity;
	Bus()
	{
		super();
		capacity = 20;
		System.out.println("执行公交车类的无参构造方法。");
	}
	Bus(int capacity)
	{
		super();
		this.capacity = capacity;
		System.out.println("执行公交车类的有参构造方法。");
	}
	public void print()
	{
		super.print();
		System.out.println("[Bus]---speed:"+super.speed+",capacity:"+capacity+",父类的capacity:"+capacity);
	}

	
	
}

package bzu.bb;

import bzu.aa.Car;

public class Test {

	public static void main(String[] args) {
		// TODO Auto-generated method stub
		Car car = new Car();
		int speed = 0;
		while(speed<50)
		{
			speed = car.speedup();
		}
		car.print();
		while(speed>20)
		{
			speed = car.speeddown();
		}
		car.print();
		Bus bus= new Bus(25);
		bus.print();
	}

}