Question

早上好，如果这个问题很复杂/令人困惑，我道歉。我参加了一个简介java课程，我的一项任务遇到了一些困难！你们这里的人似乎对所有事情都有答案，所以我知道你们可以提供帮助！

这项任务是为某些形状（矩形和三角形）创建规范，但必须按原样实现：

所有形状必须实现计算界面，计算其面积/周长。 shapemanger类将计算出的形状存储在一个能够存储多达10个对象的数组中......

public class App
{
    public static void main(String[] args)
    {

        ShapeManager sm      =    new ShapeManager();

        Rectangle       r1  =   new Rectangle(100,120,10,13);
        sm.addShape(r1);

        sm.dump();
      }
}

public interface Calculated
{
     public double calculateArea();

     public double calculatePerimeter();

     public void dump();
}

public class Rectangle implements Calculated
{
    private int xCoord, yCoord, length, width, rectangleArea, rectanglePerimeter;
    public Calculated rectangleShape;

    public Rectangle(int XCoord, int YCoord, int Length, int Width)
    {
        XCoord = xCoord;
        YCoord = yCoord;
        Length = length;
        Width = width;
    }

    public double calculateArea()
    {
        rectangleArea = length * width;
        return rectangleArea;
    }

    public double calculatePerimeter()
    {
        rectanglePerimeter = (length *2) + (width * 2);
        return rectanglePerimeter;
    }

    public void dump()
    {
        System.out.println("The Area of the rectangle = " + rectangleArea);
        System.out.println("The Perimeter of the rectangle =" + rectanglePerimeter);
    }

}


public class ShapeManager
{
    private Calculated[] calcArray;
    private Calculated rectangle;
    public Calculated shape;

    public ShapeManager()
    {
        calcArray = new Calculated[10];
    }

    public void addShape(Calculated s)
    {
        int address = 0;
        while (calcArray[address] != null)
        {
            address++;
        }

        calcArray[address] = s;
    }

    public void dump()
    {
        for (int x = 0; x <= 9; x++)
        {

            if (calcArray[x] !=null)
            {
                calcArray[x].dump();
            }
        }
    }
    }

目前我的输出是：

矩形区域= 0 矩形的周长= 0

我真的被困在我做错了什么，以及为什么输出没有正确计算。非常感谢您对此的任何帮助，非常感谢您的帮助和耐心！

Allyso

Answer 1

将dump方法更改为：

public void dump()
{
    System.out.println("The Area of the rectangle = " + calculateArea());
    System.out.println("The Perimeter of the rectangle =" + calculatePerimeter());
}

您可以通过删除以下两个字段来进一步改进：rectangleArea和rectanglePerimeter并使计算函数如下：

public double calculateArea()
{  
    return length * width;
}

现在你也节省了一些内存。然后，我会将方法重命名为getArea和getPerimeter。

Answer 2

你的设计需要修剪一些糟糕的设计选择，比如缓存区域等：

public interface Shape {
    public double getArea();
    public double getPerimeter();
    public void dump();
}

public class Rectangle implements Shape {
    private int xCoord, yCoord, length, width;

    public Rectangle(int XCoord, int YCoord, int Length, int Width) {
        XCoord = xCoord;
        YCoord = yCoord;
        Length = length;
        Width = width;
    }

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

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

    public void dump() {
        System.out.println("The Area of the rectangle = " + getArea());
        System.out.println("The Perimeter of the rectangle =" + getPerimeter());
    }
}

Answer 3

将'Rectangle'类中的函数'dump'替换为如下：

public void dump()
{
    this.calculateArea();
    this.calculatePerimeter();
    System.out.println("The Area of the rectangle = " + rectangleArea);
    System.out.println("The Perimeter of the rectangle =" + rectanglePerimeter);
}

您也可以在ShapeManager中的'dump'函数内的循环中执行此操作。

从实现的类向数组添加对象

3 个答案: