Question

我试图创建一个类CircleClass但我有一些错误，我无法理解。我可以帮助找到错误吗？

import java.util.*;
public final class CircleClass
{
    //class fields
    private int diameter;
    private double area;

    /*Default Constructor
     *IMPORT none
     *EXPORT address of new CircleClass object
     *ASSERTION area 0 diameter 0 is default
     */
    public CircleClass()
    {
        area = 0.0;
        diameter = 0;
    }

    /*copy constructor
     *IMPORT inCircle (CircleClass)
     *EXPORT address of new CircleClass object
     *ASSERTION creates an object with an identical object state as the import
     */
    public CircleClass(CircleClass inCircleClass)
    {
        area = inCircleClass.getArea ();
        diameter = inCircleClass.getDiameter ();
    }

    /*alternate constructor
     *IMPORT inDiameter (integer)
     *EXPORT address of new Circle object
     *ASSERTION creates an object if imports are valid or fails otherwise
     */
    public CircleClass (int inDiameter)
    {
        if (validateNumber (inDiameter))
        {
            diameter = inDiameter;
            area = calcArea (diameter);
        }
        else
        {
            throw new IllegalArgumentException("invalid value");
        }
    }
    /*SUB setArea
     *IMPORT area (real)
     *EXPORT none
     *ASSERTION sets the area if import is valid
     */
    public void setArea (double area)
    {
        if (area >= 0.0)
        {
            area = inArea;
        }
        else
        {
            throw new IllegalArgumentException("invalid area value");
        }
    }

    /*SUB setDiameter
     *IMPORT inDiameter (integer)
     *EXPORT none
     *ASSERTION sets diater if valid
     */
    public void setDiameter (int inDiameter)
    {
        if ( validateNumber(inDiameter))
        {
            diameter = inDiameter;
        }
        else
        {
            throw new IllegalArgumentException("invalid diameter");
        }
    }

    //ACCESSORS
    public int getDiameter ()
    {
        return diameter;
    }

    public double getArea ()
    {
        return area;
    }
    //SUB equals
    //IMPORT diameter
    //EXPORT same (boolean)
    //ASSERTION same = true if diameter is same as inDiameter
    public boolean equals (int diameter)
    {
        boolean same = false;
        if (diameter == inDiameter)
        {
            same = true;
        }
        return same;
    }

    //SUB equals
    //IMPORT inObject
    //EXPORT same (booleana)
    public boolean equals (Object inObject)
    {
        boolean same = false;
        if (inObject instanceof CircleClass)
        {
            CircleClass inCircle = (CircleClass) inObject;
            same = (diameter == inCircle.getDiameter);
        }
    }

    //SUB clone
    //IMPORT none
    //EXPORT cloneCircleClass (Object)
    //ASSERTION returns cloned object of current object
    public Object clone ()
    {
        CircleClass cloneCircleClass;
        cloneCircleClass = new CircleClass ( diameter, area);
        return cloneCircleClass;
   }
    //PRIVATE SUB validateNumber
    //IMPORT inDiameter
    //EXPORT valid
    //ASSERTION number should be gtreater or equal to 0
    private boolean validateNumber (int inDiameter)
    {
        return (inDiameter >= 0);
    }

    //SUB calcArea
    //IMPORT inDiameter
    //EXPORT area
    //ASSERTION calculates area
    private boolean calcArea (int diameter)
    {
        double radius, area;
        radius = (double)diameter / 2.0;
        area = Math.PI * radius * radius;
        return area;
    }
}

我得到的错误是boolean不能转换为double

发现符号错误

并没有为circleClass

找到合适的构造函数

我正在制作类对象，所以我没有idead最后一个错误的含义。谢谢你的帮助

Answer 1

您的函数boolean calcArea(int diameter)返回布尔值。应该只是double
您尚未创建像public CircleClass (int diameter, gouble area) {}

在java中，最好在{之后写()（不是从新行开始）

public void setArea(double area) {
    if (area >= 0.0) {
        this.area = area;
    } else {
        throw new IllegalArgumentException("invalid area value");
    }
}

这个setter函数是正确的。看看你的并纠正别人。

还有更多错误，但请尝试修复这些错误。

用构造函数，访问器和变换器创建一个Circle类

1 个答案: