Shapes Toolbox 获取长度和宽度的输入并打印它们

Question

我必须制作一个带有正方形、矩形、圆形和三角形的形状工具箱。基本上，用户输入形状，然后是长度、宽度、高度、周长等，程序将输出形状本身以及说明长度、宽度面积、周长等的文字。在你的帮助下，我已经把正方形类放下了，真棒人们，现在我正在研究矩形类并遇到了问题。我将在这里发布我的主要方法和我的矩形类，我还将发布我的方形类作为参考，因为它完美地工作。什么让我是公共的矩形框（整数宽度）。当只有一个输入是长度时，这对于方形非常有用，但我正在尝试弄清楚如何将第二个输入添加到宽度类中，因为这个类也需要该参数。

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没有完全理解这个语句在做什么，我只知道它有效。我的意思是我知道它是一个接受并设置长度的构造函数，但我不明白它的限制，因为我不明白为什么我不能像宽度一样制作另一个接受宽度输入的构造函数。

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

Answer 1

您不能使用具有相同参数的两个构造函数。您必须为您的 Rectanglebox 创建第二个构造函数，例如：

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

在你的 Main.java 中你必须写：

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);