homework3

1.简述重载(Overload)与重写(Override)的区别。

 重载(Overload)：在同一个类中，方法名相同，参数列表不同(参数个数不同，参数类型不同，参数顺序不同)，与返回值类型无关
 重写(Override)：在父类与子类之间，方法名相同，输入参数和返回值的类型(或子类型)完全相同，子类的权限应当比父类更严格

2.完成刺客刺杀总统的场景，要求：刺杀成功后，将刺客的名字和总统的名字都显示出来

//测试类
package org.westos.homework3;
public class AssassinationTest {

	public static void main(String[] args) {
		// TODO Auto-generated method stub
		President president=new President("林肯",56,"男");
		Killer killer=new Killer();
		killer.setName("约翰·韦克斯");
		killer.setAge(32);
		killer.setSex("男");
		Assassination.assassination(president, killer);
	}

}

//总统类
package org.westos.homework3;
public class President {
	private String name;
	private int age;
	private String sex;

	public President() {
	}

	public President(String name, int age, String sex) {
		this.name = name;
		this.age = age;
		this.sex = sex;
	}

	public void setName(String name) {
		this.name = name;
	}

	public String getName() {
		return name;
	}

	public int getAge() {
		return age;
	}

	public void setAge(int age) {
		if(age<0 || age>=120)
		{
			System.out.println("年龄无效");
		}
		else{
			this.age = age;	
		}
		
	}

	public String getSex() {
		return sex;
	}

	public void setSex(String sex) {
		if(sex.equals("男") || sex.equals("女"))
		{
			this.sex = sex;
		}
		else {
			System.out.println("无效性别");
		}
		
	}

}

//杀手类
package org.westos.homework3;
public class Killer {
	private String name;
	private int age;
	private String sex;

	public Killer() {
	}

	public Killer(String name, int age, String sex) {
		this.name = name;
		this.age = age;
		this.sex = sex;
	}

	public void setName(String name) {
		this.name = name;
	}

	public String getName() {
		return name;
	}

	public int getAge() {
		return age;
	}

	public void setAge(int age) {
		if (age < 0 || age >= 120) {
			System.out.println("年龄无效");
		} else {
			this.age = age;
		}

	}

	public String getSex() {
		return sex;
	}

	public void setSex(String sex) {
		if (sex.equals("男") || sex.equals("女")) {
			this.sex = sex;
		} else {
			System.out.println("无效性别");
		}

	}

}

//刺杀类
package org.westos.homework3;
public class Assassination {
	
	public static void assassination(President president,Killer killer)
	{
		System.out.println(president.getName()+"被"+killer.getName()+"刺杀了");
	}

}

3.建立一个长方形的类 包括属性，长、宽 

1） 在构造方法中，给长方形的属性初始化。

 2） 写两个方法，分别求出长方形的周长和面积。

 3） 写一个方法，以长方形的对象为参数，求出两个长方形的周长差。

//测试类
package org.westos.komework3_2;
public class RectangleTest {

	public static void main(String[] args) {
		// TODO Auto-generated method stub
		Rectangle rectangle=new Rectangle(5,3);
		Rectangle rectangle2=new Rectangle(6,4);
		System.out.println("长度为"+rectangle.getLength()+",宽度为"+rectangle.getWidth()+"的矩形的面积为："+rectangle.rectangleArea());
		System.out.println("长度为"+rectangle.getLength()+",宽度为"+rectangle.getWidth()+"的矩形的周长为："+rectangle.rectanglePerimeter());
		System.out.println("长度为"+rectangle.getLength()+",宽度为"+rectangle.getWidth()+"与长度为"+rectangle2.getLength()+",宽度为"+rectangle2.getWidth()+"的矩形周长之差为:"+rectangle2.recangleSubtract(rectangle, rectangle2));
	}

}

//矩形类
package org.westos.komework3_2;
public class Rectangle {
	private double length;
	private double width;
	public Rectangle(){
		
	}
	public Rectangle(double length, double width) {
		this.length = length;
		this.width = width;
	}
	//获取矩形的长
	public double getLength(){
		return length;
	}
	//获取矩形的宽
	public double getWidth(){
		return width;
	}
	//求矩形面积
	public double rectangleArea(){
		if(length<0 || width<0){
			return 0;
		}
		return length*width;
	}
	//求矩形周长
	public double  rectanglePerimeter() {
		if(length<0 || width<0){
			return 0;
		}
		return (length+width)*2;
	}
	//求两个矩形周长之差
	public double recangleSubtract(Rectangle rectangle,Rectangle rectangle2)
	{
		return Math.abs(rectangle.rectanglePerimeter()-rectangle2.rectanglePerimeter());
	}

}

4. 创建拥有继承结构的两个类，两个类拥有相同定义的show（）方法，但是方法体中 的内容不同，分别创建一个父类对象和子类对象，分别调用show()方法，观察结果。

//测试类
package org.westos.homework3_3;
public class Test {

	public static void main(String[] args) {
		// TODO Auto-generated method stub
		Person person = new Person();
		Student student = new Student();
		person.show();
		student.show();

	}

}

//Person类
package org.westos.homework3_3;
public class Person {
	private String name;
	private int age;
	private String sex;
	public Person() {
		super();
	}
	public Person(String name, int age, String sex) {
		super();
		this.name = name;
		this.age = age;
		this.sex = sex;
	}
	public void show(){
		System.out.println("我是父类");
	}

}

//Student类
package org.westos.homework3_3;
public class Student extends Person {
	private String num; //学号
	public Student() {
		super();
	}
	public Student(String num) {
		super();
		this.num = num;
	}
	public void show(){
		System.out.println("我是子类");
	}
}