【Java】抽象类作业

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package test1;

import java.util.Scanner;

public class Program{

    public static void main(String[] args)
    {
        Scanner scanner=new Scanner(System.in);
        System.out.println("Square:\nPlease enter the dim of Square:");
        Square square=new Square(scanner.nextDouble());//实例化正方形对象
        System.out.println("Area:"+square.callArea()+",Perimeter:"+square.callPerimeter());//打印数据
        System.out.println("Rectangle:\nPlease enter the Width of Rectangle:");
        double width=scanner.nextDouble();
        System.out.println("Please enter the Length of Rectangle:");
        double length=scanner.nextDouble();//实例化长方形对象
        Rectangle rectangle=new Rectangle(length,width);
        System.out.println("Area:"+rectangle.callArea()+",Perimeter:"+rectangle.callPerimeter());//打印数据
    }

}

abstract class Shape//建立抽象类Shape
{
    double dim;//一个边长度
    public Shape(double dim)
    {
        this.dim=dim;
    }//使用构造函数初始化这条边
    public abstract double callArea();//建立抽象函数“求面积”
    public abstract double callPerimeter();//建立抽象函数“求周长”
}

class Square extends Shape//建立正方形类
{
    public Square(double dim)
    {
        super(dim);
    }

    public double callArea()
    {
        return dim*dim;
    }//实现求面积方法

    public double callPerimeter()
    {
        return dim*4;
    }//实现求周长方法
}

class Rectangle extends Shape//建立矩形类
{
    double dim2;//矩形有两条不一样长的边，故再建立一个字段存放第二条边的长度

    public Rectangle(double length,double width)
    {
        super(length);//一条边由父类Shape的构造函数初始化
        dim2=width;//另一条边在此初始化
    }//将两条边初始化

    public double callArea()
    {
        return dim*dim2;
    }//实现求面积的方法

    public double callPerimeter() {
        return (dim+dim2)*2;
    }//实现求周长的方法
}