正在类层次结构中设置变量

Question

我正在编写一个程序，根据学校的类层次结构来查找形状的体积和表面积。我试图在主类中获得一个方法来设置抽象类中的变量，但它不起作用。

这是主要类别：

import java.util.Scanner;
public class ShapeDriver{
  public double cubeSide;
  public static void main(String[] args){
    Scanner input = new Scanner(System.in);
    System.out.println("Enter 1 for cube, 2 for rectangular prism, 3 for cylinder, 4 for cone, or 5 for sphere.");
    int shapeNum = input.nextInt();
    if(shapeNum == 1){
      ShapeDriver shDriver = new ShapeDriver();
      PrismSet prism = new PrismSet();
      System.out.println("Enter the length of a side of the cube.");
      shDriver.cubeSide = input.nextDouble();
      prism.setCubeLength();
      Cube cu = new Cube();
      System.out.println("Surface area: " + cu.surfaceArea());
      System.out.println("Volume: " + cu.volume());
    }
  }
}

这是一个抽象类，其中包含我想要更改的变量prismWidth和prismHeight：

public abstract class Prisms implements ShapeFunctions{
  public double prismWidth;
  public double prismHeight;
  public double prismDepth;
  public double findFrontBackFaceArea(double prismHeight, double prismWidth){
    double prismFrontBackFaceArea = prismHeight * prismWidth * 2;
    return prismFrontBackFaceArea;
  }
  public double findRightLeftFaceArea(double prismHeight, double prismDepth){
    double prismRightLeftFaceArea = prismHeight * prismWidth * 2;
    return prismRightLeftFaceArea;
  }
  public double findTopBottomFaceArea(double prismWidth, double prismDepth){
    double prismTopBottomFaceArea = prismWidth * prismDepth * 2;
    return prismTopBottomFaceArea;
  }
}

这是我写的试图访问抽象类中变量的类：

public class PrismSet extends Prisms{
  public double surfaceAreaHolder;
  public double volumeHolder;
  public void setCubeLength(){
    ShapeDriver sDriver = new ShapeDriver();
    super.prismHeight = sDriver.cubeSide;
    super.prismWidth = sDriver.cubeSide;
  }
  public double surfaceArea(){
    return surfaceAreaHolder;
  }
  public double volume(){
    return volumeHolder;
  }

}

当我输入一个数字作为cubeSide的值时，它会为表面积和体积返回0.0。我做错了什么？

编辑：这是Cube类：

public class Cube extends Prisms implements ShapeFunctions{
  public double surfaceArea(){
    double cubeSurfaceArea = super.findFrontBackFaceArea(super.prismHeight, super.prismWidth) * 3;
    return cubeSurfaceArea;
  }
  public double volume(){
    double cubeVolume = Math.pow(super.prismWidth, 3);
    return cubeVolume;
  }
 }

Answer 1

尝试在棱镜集中修改此方法

public void setCubeLength(ShapeDriver sDriver){
 super.prismHeight = sDriver.cubeSide;
 super.prismWidth = sDriver.cubeSide;
}

并将其传递给shDriver

---

同时将ShapeDriver类更改为：

public static void main(String[] args){
    Scanner input = new Scanner(System.in);
    System.out.println("Enter 1 for cube, 2 for rectangular prism, 3 for cylinder, 4 for cone, or 5 for sphere.");
    int shapeNum = input.nextInt();
    if(shapeNum == 1){
      ShapeDriver shDriver = new ShapeDriver();
      Cube cube = new Cube();
      System.out.println("Enter the length of a side of the cube.");
      shDriver.cubeSide = input.nextDouble();
      cube.setCubeLength(shDriver); // change this also
      System.out.println("Surface area: " + cu.surfaceArea());
      System.out.println("Volume: " + cu.volume());
    }
  }

---

好吧，所以，我认为你希望你的立方体扩展棱镜集，否则，我不确定你想要实现什么。我设法用这个代码做到了这一点：

import java.util.Scanner;
public class ShapeDriver {
    public double cubeSide;
    public static void main(String[] args) {
        Scanner input = new Scanner(System.in);
        System.out.println("Enter 1 for cube, 2 for rectangular prism, 3 for cylinder, 4 for cone, or 5 for sphere.");
        int shapeNum = input.nextInt();
        if (shapeNum == 1) {
            ShapeDriver shDriver = new ShapeDriver();
            Cube cube = new Cube();
            System.out.println("Enter the length of a side of the cube.");
            shDriver.cubeSide = input.nextDouble();
            cube.setCubeLength(shDriver);
            System.out.println("Surface area: " + cube.surfaceArea());
            System.out.println("Volume: " + cube.volume());
        }
    }
}

棱镜：

public abstract class Prisms implements ShapeFunctions {
    public double prismWidth;
    public double prismHeight;
    public double prismDepth;
    public double findFrontBackFaceArea(double prismHeight, double prismWidth) {
        double prismFrontBackFaceArea = prismHeight * prismWidth * 2;
        return prismFrontBackFaceArea;
    }
    public double findRightLeftFaceArea(double prismHeight, double prismDepth) {
        double prismRightLeftFaceArea = prismHeight * prismWidth * 2;
        return prismRightLeftFaceArea;
    }
    public double findTopBottomFaceArea(double prismWidth, double prismDepth) {
        double prismTopBottomFaceArea = prismWidth * prismDepth * 2;
        return prismTopBottomFaceArea;
    }
}

棱镜集

public class PrismSet extends Prisms {
    public double surfaceAreaHolder;
    public double volumeHolder;
    public void setCubeLength(ShapeDriver sDriver) {
        super.prismHeight = sDriver.cubeSide;
        super.prismWidth = sDriver.cubeSide;
    }
    public double surfaceArea() {
        return surfaceAreaHolder;
    }
    public double volume() {
        return volumeHolder;
    }
}

立方体

public class Cube extends PrismSet implements ShapeFunctions {
    public double surfaceArea() {
        double cubeSurfaceArea = super.findFrontBackFaceArea(super.prismHeight, super.prismWidth) * 3;
        return cubeSurfaceArea;
    }
    public double volume() {
        double cubeVolume = Math.pow(super.prismWidth, 3);
        return cubeVolume;
    }
}