Java （Triangle类）设计一个名为Triangle的类，该类扩展了GeometricObject

该类包含：

• 三个名为side1、side2和side3的double数据字段，默认值1.0表示三角形的三条边

• 一种无参数构造函数，用于创建具有指定的边1、边2和边3的三角形

• 所有三个数据字段的访问器方法

• 名为getArea（）的方法，该方法返回三角形的面积

• 名为getPermiture（）的方法返回此三角形的周长

*名为toString（）的方法，该方法返回三角形的字符串描述

有关计算三角形面积的公式，请参见编程练习2.15（java编程入门第9版） toString（）方法实现如下：

return“Triangle:side1=“+side1+”side2=“+side2+”side3”+side3

为类Triangle和GeometricObject绘制UML图，并实现这些类。编写一个测试程序，提示用户输入三角形的三条边、颜色和布尔值，以指示三角形是否已填充。程序应使用这些边创建一个三角形对象，并使用输入设置颜色和填充属性。程序应显示面积、周长、颜色和真或假，以指示填充与否

---

我在练习中遇到的问题是测试程序

如果你能帮助我，告诉我如何从输入中生成三角形，我将非常感激

我目前的代码是：

几何体对象

public class GeometricObject {
    private String color = " white ";
    private boolean filled;
    private java.util.Date dateCreated;

    public GeometricObject() {
        dateCreated = new java.util.Date();
    }

    public GeometricObject(String color, boolean filled) {
        dateCreated = new java.util.Date();
        this.color = color;
        this.filled = filled;   
    }

    public String getColor() {
        return color;
    }

    public void setColor(String color) {
        this.color = color;
    }

    public boolean isFilled() {
        return filled;
    }

    public void setFilled(boolean filled) {
        this.filled = filled;
    }

    public java.util.Date getDateCreated() {
        return dateCreated;
    }

    public String toString() {
        return "Created on " + dateCreated + "\n color: " + color + " and filled ";                 
    }   
 }

三角计划

public class Triangle extends GeometricObject {
    private double side1 = 1.0;
    private double side2 = 1.0;
    private double side3 = 1.0;

    public Triangle() {
    }

    public Triangle(double side1, double side2, double side3) {
        this.side1 = side1;
        this.side2 = side2;
        this.side3 = side3;
    }

    public double setSide1() {
        return side1;
    }

    public double setSide2() {
        return side2;
    }

    public double setSide3() {
        return side3;
    }

    public void setSide1(double side1) {
        this.side1 = side1;
    }

    public void setSide2(double side2) {
        this.side2 = side2;
    }

    public void setSide3(double side3) {
        this.side3 = side2;
    }

    public double getArea() {
        return (side1 + side2 + side3) / 2;
    }

    public double getPerimeter() {
        return side1 + side2 + side3;
    }

    public String toString() {
    return " Triangle: Side 1 = " + side1 + " Side 2 = " + side2
           + " Side 3 = " + side3;
    }
}

测试程序。

import java.util.Scanner;

public class TestTriangle  {
    private double side1 = 1.0;
    private double side2 = 1.0;
    private double side3 = 1.0;

    public static void main(String[] args) {
        Scanner input = new Scanner(System.in);

        System.out.println("Enter three sides of the Triangle");
        double side1 = input.nextDouble();
        double side2 = input.nextDouble();
        double side3 = input.nextDouble();

        System.out.println("Enter the color of the Triangle");
        String color = input.next();

        System.out.println(" Is the Triangle filled? Reply with 'True' or 'False' ");

        String filled = input.next(); 
    }
    {
        new Triangle(side1, side2, side3);
        //How do i get the information into theTriangle?

        System.out.println("The Triangle Sides are \n side 1: " + side1 + "\n Side 2: " + side2 + "\n Side 3: " + side3);
        System.out.println("The Triangle's Area is " + (side1 + side2 + side3) / 2);
        System.out.println("The Triangle's Perimeter is "
                           + (side1 + side2 + side3));
        System.out.println("The Triangle's Color is " + //what goes here?);
        System.out.println("Is the Triangle filled? " + //what goes here?);

    }
}

---

您需要像这样创建一个新的

三角形

对象，以便有一个引用

Trangle triangle = new Triangle(side1, side2, side3);

  //     ^^^^^^ This is the most important thing you're missing.  You need a reference
  //            point for your object.  That's the only way you can access it's
  //            properties.    

您还需要设置它的

填充

和

颜色

属性

triangle.setFilled(filled);
triangle.setColor(color);

然后，您可以像这样调用其方法：

System.out.println("The Triangle Sides are \n side 1: " 
       + triangle.getSide1() + "\n Side 2: " + triangle.getSide2() 
       + "\n Side 3: " + triangle.getSide3());

System.out.println("The Triangle's Area is " + triangle.getArea());

System.out.println("The Triangle's Perimeter is " + triangle.getPerimeter();

System.out.println("The Triangle's Color is " + triangle.getColor());
System.out.println("Is the Triangle filled? " + triangle.isFilled());

您可以访问

GeometricObject

的

isFilled（）

、

setFilled（）

、

getColor（）

和

setColor（）

，因为

三角形

是

GeometricObject

（

扩展了

），所以它继承了它的所有方法

顺便说一下，这不是计算三角形面积的方法：

public double getArea() {
    return (side1 + side2 + side3) / 2;   // This is so wrong
}

检查这个正确的公式

编辑：代码有另一个问题

编辑：三角形公式

public double getArea() {
    int p = getPerimeter() / 2
    return Math.sqrt(p * ((p - side1) * (p - side2) * (p - side3));
}

---

几何对象

package geometricobject;
import java.util.Scanner;

/**
 *
 * @author Kirubel 
 */

abstract class GeometricObject
{

private String color = "white";
private boolean filled;
private java.util.Date dateCreated;
/** Construct a default geometric object */
protected GeometricObject()
{


}

/** Construct a geometric object with color and filled value */
protected GeometricObject(String color, boolean filled)
{
    dateCreated = new java.util.Date();
    this.color = color;
    this.filled = filled;
}

/** Return color */
public String getColor()
{
    return color;
}

/** Set a new color */
public void setColor(String color)
{
    this.color = color;
}

/** Return filled. Since filled is boolean ,
 * the get method is named isFilled */
public boolean isFilled()
{
    return filled;
}

/** Set a new filled */
public void setFilled(boolean filled)
{
    this.filled = filled;
}

/** Get dateCreated */
public java.util.Date getDateCreated()
{
    return dateCreated;
}

@Override
public String toString() {
    return "created on " + dateCreated + "\ncolor: " + color +
            " and filled: " + filled;
}

/** Abstract method getArea */
public abstract double getArea();

/** Abstract method getPerimeter */
public abstract double getPerimeter();

/**
 * @param args the command line arguments
 */

}

class Triangle extends GeometricObject
{

public double side1;
public double side2;
public double side3;
public Triangle() //default constructor
{
    side1=1.0;
    side2=1.0;
    side3=1.0;
}

public Triangle(double side1,double side2,double side3) //peremetrised constructor
{
    this.side1=side1;
    this.side2=side2;
    this.side3=side3;
}
@Override
public double getPerimeter() //function for getting peremeter for triangle
{
    return(side1+side2+side3) ;

}



@Override
// function for getting area of triangle
public double getArea() 
{
    double area,s;
    s=side1+side2+side3;
    area = Math.sqrt(s * (s- side1) * (s - side2) * (s - side3));
    return(area);

}
@Override
public String toString()//to print the data
{
    String s;
    s="Triangle:side1 "+ side1 +" side2 " + side2 + " side3 "+side3;
    return(s);
}

private String getSide1() {
    // TODO Auto-generated method stub
    return null;
}

private String getPerimeter(double d) {
    // TODO Auto-generated method stub
    return null;
}

private String getPerimeter(String string) {
    // TODO Auto-generated method stub
    return null;
}

private String getSide3() {
    // TODO Auto-generated method stub
    return null;
}

private String getSide2() {
    // TODO Auto-generated method stub
    return null;
}


public static void main(String args[])
{

    Scanner input = new Scanner(System.in);

    System.out.println("Enter three sides of the Triangle");
    double side1 = input.nextDouble();
    double side2 = input.nextDouble();
    double side3 = input.nextDouble();

    System.out.println("Enter the color of the Triangle");
    String color = input.next();

    System.out.println(" Is the Triangle filled? Reply with 'True' or 'False' ");

    String filled = input.next(); 
}


{
    Triangle triangle = new Triangle(side1, side2, side3);
    triangle.setFilled(isFilled());
    triangle.setColor(getColor());

    // Display 
    System.out.println("The Triangle Sides are \n side 1: " 
            + triangle.getSide1() + "\n Side 2: " + triangle.getSide2() 
            + "\n Side 3: " + triangle.getSide3());

    System.out.println("The Triangle's Area is " + triangle.getArea());
    System.out.println("The Triangle's Perimeter is " + triangle.getPerimeter());
    System.out.println("The Triangle's Color is " + triangle.getColor());
    System.out.println("Is the Triangle filled? " + triangle.isFilled());
}
}

三角形

package geometricobject;
import java.util.Scanner;

/**
 *
 * @author Kirubel 
 */

abstract class GeometricObject
{

private String color = "white";
private boolean filled;
private java.util.Date dateCreated;
/** Construct a default geometric object */
protected GeometricObject()
{


}

/** Construct a geometric object with color and filled value */
protected GeometricObject(String color, boolean filled)
{
    dateCreated = new java.util.Date();
    this.color = color;
    this.filled = filled;
}

/** Return color */
public String getColor()
{
    return color;
}

/** Set a new color */
public void setColor(String color)
{
    this.color = color;
}

/** Return filled. Since filled is boolean ,
 * the get method is named isFilled */
public boolean isFilled()
{
    return filled;
}

/** Set a new filled */
public void setFilled(boolean filled)
{
    this.filled = filled;
}

/** Get dateCreated */
public java.util.Date getDateCreated()
{
    return dateCreated;
}

@Override
public String toString() {
    return "created on " + dateCreated + "\ncolor: " + color +
            " and filled: " + filled;
}

/** Abstract method getArea */
public abstract double getArea();

/** Abstract method getPerimeter */
public abstract double getPerimeter();

/**
 * @param args the command line arguments
 */

}

class Triangle extends GeometricObject
{

public double side1;
public double side2;
public double side3;
public Triangle() //default constructor
{
    side1=1.0;
    side2=1.0;
    side3=1.0;
}

public Triangle(double side1,double side2,double side3) //peremetrised constructor
{
    this.side1=side1;
    this.side2=side2;
    this.side3=side3;
}
@Override
public double getPerimeter() //function for getting peremeter for triangle
{
    return(side1+side2+side3) ;

}



@Override
// function for getting area of triangle
public double getArea() 
{
    double area,s;
    s=side1+side2+side3;
    area = Math.sqrt(s * (s- side1) * (s - side2) * (s - side3));
    return(area);

}
@Override
public String toString()//to print the data
{
    String s;
    s="Triangle:side1 "+ side1 +" side2 " + side2 + " side3 "+side3;
    return(s);
}

private String getSide1() {
    // TODO Auto-generated method stub
    return null;
}

private String getPerimeter(double d) {
    // TODO Auto-generated method stub
    return null;
}

private String getPerimeter(String string) {
    // TODO Auto-generated method stub
    return null;
}

private String getSide3() {
    // TODO Auto-generated method stub
    return null;
}

private String getSide2() {
    // TODO Auto-generated method stub
    return null;
}


public static void main(String args[])
{

    Scanner input = new Scanner(System.in);

    System.out.println("Enter three sides of the Triangle");
    double side1 = input.nextDouble();
    double side2 = input.nextDouble();
    double side3 = input.nextDouble();

    System.out.println("Enter the color of the Triangle");
    String color = input.next();

    System.out.println(" Is the Triangle filled? Reply with 'True' or 'False' ");

    String filled = input.next(); 
}


{
    Triangle triangle = new Triangle(side1, side2, side3);
    triangle.setFilled(isFilled());
    triangle.setColor(getColor());

    // Display 
    System.out.println("The Triangle Sides are \n side 1: " 
            + triangle.getSide1() + "\n Side 2: " + triangle.getSide2() 
            + "\n Side 3: " + triangle.getSide3());

    System.out.println("The Triangle's Area is " + triangle.getArea());
    System.out.println("The Triangle's Perimeter is " + triangle.getPerimeter());
    System.out.println("The Triangle's Color is " + triangle.getColor());
    System.out.println("Is the Triangle filled? " + triangle.isFilled());
}
}

---

新三角形（侧1、侧2、侧3）

？好的，非常感谢您的快速回复。我添加了你建议的代码，现在我离目标更近了！嗨，谢谢你的回答。颜色和填充都给了我错误<代码>三角形=新三角形（边1、边2、边3）；三角形。设置填充（填充）；三角形。设置颜色（颜色）还有所有

三角形.getSide（））

in`System.out.println（“三角形边是\n边1:“+triangle.getSide1（）+”\n边2:“+triangle.getSide2（）+”\n边3:“+triangle.getSide3（））”。另外，我可以使用

getColor（）

，

setColor（）

，

isFilled（）

，

setFilled（），
从
GeometricObject
当我需要根据输入生成三角形时？好的，我现在得到的错误如下：在这些行上
System.out.println（“三角形边是\n边1:+triangle.getSide1（）+”\n边2:+triangle.getSide2（）+”\n边3:+triangle.getSide3（））-类型Triangle的方法getSide1（）未定义-类型Triangle的方法getSide2（）未定义-类型Triangle的方法getSide3（）未定义！非常感谢。现在差不多了：）您的triangle类中有六个方法。其中三个应该是
get
方法。那应该能解决你的问题。请接受此答案。从用户处获取输入后，它不会显示结果或答案。示例运行#1：输入三角形的1边：13输入三角形的2边：14输入三角形的3边：15输入三角形的颜色：红色输入三角形是否已填充（是/否）：是区域：84.0周长：42.0颜色：红色填充？：真实样本运行#2：输入三角形1侧：9输入三角形2侧：40输入三角形3侧：41输入三角形颜色：橙色输入三角形是否填充（是/否）：否区域：180.0周长：90.0颜色：橙色填充？：false