Question

我应该得到用户输入的三角形的颜色以及三角形的宽度和高度，但是，我甚至无法显示输出。任何提示或指示都会受到高度赞赏，因为我现在只是在学校学习抽象课程。谢谢。

三角类：

import java.util.Scanner; 

public class Triangle extends GeometricObject {
private double base;
private double height;
private int color;

public Triangle() {
}

 public static void main(String[] args) {
 System.out.println("Enter a width for triangle:");
 double base = Integer.parseInt(input.nextInt());


 System.out.println("Enter height for triangle:");

 double height = Integer.parseInt(input.nextInt());
 }

 public Triangle(double base, double height) {
 this.base = base;
 this.height = height;
 this.color = color;
 }



public double getBase() {
return base;
}


public void setWidth(double width) {
 this.base = base;
 }


 public double getHeight() {
  return height;
}

 public int getColor(){
  return color;
 }

 public void setHeight(double height) {
 this.height = height;
}
public void setColor(int color){
this.color = color;
}
@Override 
 public double getArea() {
return 0.5* base * height;
}

@Override
public double getPerimeter() {
return 2 * (base + height);
}
}

这是GeometricClass：

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

  /** Construct a default geometric object */
  protected GeometricObject() {
  dateCreated = new java.util.Date();
  }

   /** 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;
  }



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


 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();
 }

Answer 1

你的代码有很多缺陷：

1）Scanner input = new Scanner(System.in);缺失。你必须得到编译错误。

2）Integer.parseInt需要String参数。

3）为什么要将int分配给double。而是使用Double.parseDouble。

4）您的构造函数Triangle(double base, double height)有两个参数，但您仍然在编写this.color = color;。为什么呢？

5）int color;为什么颜色为int？应该是String。

6）父类中存在color。为什么要在子类上添加另一个呢？

必须遵守这些要点。

我做了一些基本的改动自己尝试其余的。这是修改后的代码：

public class Triangle extends GeometricObject {
    private double base;
    private double height;
    private int color;

    public Triangle() {
    }

    public static void main(String[] args) {
        Scanner input = new Scanner(System.in);
        System.out.println("Enter a width for triangle:");
        double base = Double.parseDouble("" + input.nextInt());

        System.out.println("Enter height for triangle:");

        double height = Double.parseDouble("" + input.nextInt());

        GeometricObject triangle = new Triangle(base, height);

        System.out.println("Area of triangle " + triangle.getArea());
        System.out.println("Perimeter of triangle " + triangle.getPerimeter());
    }

    public Triangle(double base, double height) {
        this.base = base;
        this.height = height;
    }

    public double getBase() {
        return base;
    }

    public void setWidth(double width) {
        this.base = base;
    }

    public double getHeight() {
        return height;
    }

    public int getColor() {
        return color;
    }

    public void setHeight(double height) {
        this.height = height;
    }

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

    @Override
    public double getArea() {
        return 0.5 * base * height;
    }

    @Override
    public double getPerimeter() {
        return 2 * (base + height);
    }
}

您必须通过阅读上述代码来探索自己。就像为什么我使用下面的选项：

GeometricObject triangle = new Triangle(base, height);

Answer 2

什么是input？宣布在哪里？

您应该将Scanner对象指向System.in。通过这种方式，您可以要求用户输入。

    Scanner sc = new Scanner(System.in);
    while (sc.hasNext() ) {
        System.out.println('Enter color');
        int color = Integer.parseInt(sc.nextLine());


    }

使用抽象类

2 个答案: