形状工具箱获取长度和宽度的输入并打印它们

Question

我必须做一个形状工具箱，有一个正方形，矩形，圆形和三角形。基本上，用户输入形状，然后长度，高度，周长等，程序将输出形状本身，加上文字，表示长度，宽度，面积，周长等。我已经有了square类在一些帮助下，从你们这些了不起的人，现在我正在处理矩形类，遇到了一个问题。我将在这里发布我的主要方法和我的矩形类，我也将发布我的square类作为参考，因为它工作完美。我得到的是公共矩形框（int宽）。当square只有一个输入（长度）时，这对square非常有效，但我正在尝试如何在类中添加第二个输入（宽度），因为该类也需要这个参数。

import java.awt.Graphics2D;
import java.awt.Rectangle;
import java.util.Scanner;
import javax.swing.JFrame;


public class Main {

    static int input;
    static int length;
    static int width;

    public static void main(String[] args) {

        Scanner sc1 = new Scanner(System.in);
        while(true) {
            System.out.print("\n1 for square\n2 for restangle\n3 for triangle\n4 for circle\n5 to exit\n\nWhich shape do you want? ");
            input = sc1.nextInt();
            if(input == (5)) {
                break;
            }
            if(input == (1)) {


                System.out.print("Input the length: ");
                length = sc1.nextInt();
                Square mySquare = new Square(length);

                JFrame frame = new JFrame();

                frame.setSize(300,400);
                frame.setTitle("ShapeViewer");
                frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

                frame.add(mySquare);
                frame.setVisible(true);}

            if(input==(2)) {


                System.out.print("Input the length: ");
                length = sc1.nextInt();
                System.out.print("Input the width: ");
                width = sc1.nextInt();
                Rectanglebox myRectangle = new Rectanglebox(length);

                JFrame frame2 = new JFrame();

                frame2.setSize(300,400);
                frame2.setTitle("ShapeViewer");
                frame2.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

                frame2.add(myRectangle);
                frame2.setVisible(true);
            }

            }


        }
    }

import java.util.Scanner;
import javax.swing.JComponent;
import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.Color;
import java.awt.Frame;
import java.awt.Rectangle;

public class Rectanglebox extends JComponent{

    private int length;
    private int width;

    public Rectanglebox(int length) {
        this.length = length;
    }

    public Rectanglebox(int width) {
        this.width = width;
    }

    public double getArea() {
        return length * width;
    }
    public double getPerimeter() {
        return (length * 2) + (width * 2);
    }

    public void paintComponent(Graphics g) {
        Graphics2D g2 = (Graphics2D)g;
        Rectangle square = new Rectangle(100,100,length,length);
        g2.draw(square);
        g2.drawString("Area: "+getArea(), 110, 110+length);
        g2.drawString("Perimeter: " + getPerimeter(), 200, 110+length);
        g2.drawString("Square", 110, 20);
        g2.drawString("Length: " +length, 10, 200+length);
        g2.drawString("Width" +width, 60, 200);

        g2.setColor(Color.black);
        g2.fill(square);
    }
}

import java.util.Scanner;
import javax.swing.JComponent;
import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.Color;
import java.awt.Frame;
import java.awt.Rectangle;

public class Square extends JComponent{

    private int length; 

    public Square(int length) {
        this.length = length;
    }

    public double getArea() {   
    return length * length;
    }
    public int getPerimeter() {
        return length * 4;
    }
    public void paintComponent(Graphics g) {
        Graphics2D g2 = (Graphics2D)g;
        Rectangle square = new Rectangle(50,50,length,length);
        g2.draw(square);
        g2.drawString("Area: "+getArea(), 110, 110+length);
        g2.drawString("Perimeter: " + getPerimeter(), 200, 110+length);
        g2.drawString("Square", 110, 20);
        g2.drawString("Length: " +length, 10, 110+length);
        g2.setColor(Color.black);
        g2.fill(square);
    }
}

我认为这里的主要问题是我实际上并不完全理解这句话在做什么，甚至我只知道它起作用。我的意思是，我知道它是一个接受并设置长度的构造函数，但我不理解它的限制，因为我不明白为什么我不能做另一个像它一样的width来接受width输入。

public Square(int length) {
        this.length = length;
    }

Answer 1

不能使用具有相同参数的两个构造函数。您必须为矩形框创建第二个构造函数，类似于：

public Rectanglebox(int length, int width) {
  this.length = length;
  this.width = width;
}

在main.java中，您必须编写：

if(input==(2)) {
  System.out.print("Input the length: ");  
  length = sc1.nextInt();
  System.out.print("Input the width: ");
  width = sc1.nextInt();
  Rectanglebox myRectangle = new Rectanglebox(length, width);