2024秋面向对象程序设计pta-实验二

6-1	设计一个矩形类Rectangle

class Rectangle{

double width=1;

double height= 1;

public Rectangle(){}

public Rectangle(double width, double height){

this.width=width;

this.height=height;}

public double getArea(){

return width*height;}

public double getPerimeter(){

return 2*(width+height);}

}

6-2 Book类的设计 

class Book {

private String title; // 书籍名称

private int price; // 价格

private String author; // 作者

private int year; // 出版年份

// 构造方法

public Book(String title, int price, String author, int year) {

this.title = title;

this.price = price;

this.author = author;

this.year = year;

}

// Getter 和 Setter 方法

public String getTitle() {

return title;

}

public void setTitle(String title) {

this.title = title;

}

public int getPrice() {

return price;

}

public void setPrice(int price) {

this.price = price;

}

public String getAuthor() {

return author;

}

public void setAuthor(String author) {

this.author = author;

}

public int getYear() {

return year;

}

public void setYear(int year) {

this.year = year;

}

}

6-3:根据派生类写出基类（Java）

public People() {

// 默认值

}

// 带参数的构造方法

public People(String id, String name) {

this.id = id;

this.name = name;

}

// 设置id

public void setId(String id) {

this.id = id;

}

// 设置name

public void setName(String name) {

this.name = name;

}

// 获取id

public String getId() {

return id;

}

// 获取name

public String getName() {

return name;

}

// say方法

public void say() {

System.out.println("I'm a person! My name is " + this.name + ".");

}

  

6-4 从抽象类shape类扩展出一个圆形类Circle 

class Circle extends shape{

private double radius;

public Circle(double r){

radius=r;

}

public double getArea(){

return Math.PI*radius*radius;

}

public double getPerimeter(){

return 2*Math.PI*radius;

}

}

6-5 图书和音像租赁