Question

我遇到了一项任务，我们必须构建5个类来生成一个程序，该程序执行简单的计算和处理以2D几何体表示的简单形状。

首先，它要求用户从三个选项中选择一个形状。然后它会提示输入形状的详细信息。通过给出X然后Y坐标来指定圆其中心，其后是半径。通过给出X和Y坐标指定三角形其三个角点中的每一个。通过给出X和Y坐标指定矩形两个对角线对角点。

根据此数据，系统会提示用户指定X偏移量和Y偏移。

程序创建指定的形状，也是类似的形状，其中每个点都被X和Y偏移移位。

程序然后在标准输出上报告以下内容。原始形状的细节 - 给出所有要点（一，三或四），对于一个圆，它的半径。形状的面积和周长。变形的细节。

这5个班级将是ShapeShift，Circle，Triangle，Point和Rectangle。

到目前为止我的代码如下：

矩形

public class Rectangle
{

  private final Point a;
  private final Point b;

// Constructor Method
public Rectangle(Point requiredA, Point requiredB)
{
  a = requiredA;
  b = requiredB;
}

// Get point c for the third commnadline
public Point c()
{
  return new Point(a.getXCoordinate(), b.getYCoordinate());
}// c

// Get point d for the forth commandline
public Point d()
{
  return new Point(b.getXCoordinate(), a.getYCoordinate());
} //d


public double areaOfRectangle()
{
  return (a.distance(c()) * a.distance(d()));
}

public double perimeterOfRectangle()
{
  return  (2 * (a.distance(c())) + (a.distance(d())));
}

} // Rectangle

三角

public class Triangle
{

// Triangle, has 8 values including 2 shift values.

private final Point TrianglePoint1;
private final Point TrianglePoint2;
private final Point TrianglePoint3;

// Constructor Method

public Triangle(Point requiredTrianglePoint1,
                Point requiredTriagnlePoint2,
                Point requiredTrianglePoint3)
{
  TrianglePoint1 = requiredTrianglePoint1;
  TrianglePoint2 = requiredTriagnlePoint2;
  TrianglePoint3 = requiredTrianglePoint3;
}

public double perimeterOfTriangle()
{
  return (TrianglePoint1.distance(TrianglePoint2) +
          TrianglePoint2.distance(TrianglePoint3) +
          TrianglePoint3.distance(TrianglePoint1));
} // PerimeterTriangle

// Work and return the area of the triangle
public double areaOfTriangle()
{
  double semiPerimeter = (TrianglePoint1.distance(TrianglePoint2) +
                          TrianglePoint2.distance(TrianglePoint3) +
                          TrianglePoint3.distance(TrianglePoint1) / 2);

  return Math.sqrt(semiPerimeter *
                  (semiPerimeter - TrianglePoint1.distance(TrianglePoint2)) *
                  (semiPerimeter - TrianglePoint2.distance(TrianglePoint3)) *
                  (semiPerimeter - TrianglePoint3.distance(TrianglePoint1)));
 } // AreaTriangle

环

public class Circle
{

// Use the circle to find the centre and the radius.

private final Point centre;
private final double radius;

// Construct the two values

public Circle(Point requiredCentre, double requiredRadius)
{
  centre = requiredCentre;
  radius = requiredRadius;
}

public double areaOfCircle()
{
  return (Math.PI * (Math.pow(radius, 2)));
} // areaOfCircle

public double perimeterOfCircle()
{
  return (2 * Math.PI * radius);
} //Perimeter
}// Circle

点

public class Point
{
// Two Coordinate values for each point
  private final double coordinateX;
  private final double coordinateY;

// Construct the two values
  public Point(double requiredCoordinateX, double requiredCoordinateY)
{
  coordinateX = requiredCoordinateX;
  coordinateY = requiredCoordinateY;
}

// Get the X Coordinate
public double getXCoordinate()
{
  return coordinateX;
}

// Get Y Coordinate
public double getYCoordinate()
{
  return coordinateY;
}

// The layout, when demonstrating the two values.
public String toString()
{
  return "(" + coordinateX + "," + coordinateY + ")";
} // String

// Calculate the moved coordinates, when added to xShift and yShift
public Point shift(double xShift, double yShift)
{
  return new Point (coordinateX + xShift,
                    coordinateY + yShift);
} //movedPoint

// Calculate the distance between two points
public double distance(Point other)
{
  return Math.sqrt(Math.pow((coordinateX - other.coordinateX), 2) +
                   Math.pow((coordinateY - other.coordinateY), 2));
} // Distance calculated

} // Point

变身

import java.util.Scanner;

public class ShapeShift
{
// A scanner to interact with the user.
  private static Scanner inputScanner = new Scanner(System.in);


// Helper method to read a point from the input.
  public static Point inputPoint(String prompt)
{
  System.out.print(prompt);
  double x = inputScanner.nextDouble();
  double y = inputScanner.nextDouble();
  return new Point(x, y);
} // inputPoint


// The X and Y amount to shift the first shape to get the second.
public static double xShift, yShift;

public ShapeShift(double shiftX, double shiftY)
{
  xShift = shiftX;
  yShift = shiftY;
}

 // Helper method to read the X and Y shifts.
private static void inputXYShifts()
{
  System.out.print("Enter the offset as X Y: ");
  double xShift = inputScanner.nextDouble();
  double yShift = inputScanner.nextDouble();
} // inputXYShifts


 // The main method.
public static void main(String[] args)
{
  // Obtain shape choice.
  System.out.print("Choose circle (1), triangle (2), rectangle (3): ");
  int shapeChoice = inputScanner.nextInt();

  // Process the shape based on the choice.
  switch (shapeChoice)
  {
    // Circle.
    case 1:
      Point centre = inputPoint("Enter the centre as X Y: ");
      System.out.print("Enter the radius: ");
      double radius = inputScanner.nextDouble();
      Circle originalCircle = new Circle(centre, radius);
      inputXYShifts();
      Circle shiftedCircle = originalCircle.shift(xShift, yShift);
      System.out.println();
      System.out.println(originalCircle);
      System.out.println("has area " + originalCircle.areaOfCircle()
                         + ", perimeter " 
                         + originalCircle.perimeterOfCircle());
      System.out.println("and when shifted by X offset " + xShift
                         + " and Y offset " + yShift + ", gives");
      System.out.println(shiftedCircle);
      break;

    // Triangle.
    case 2:
      Point pointA = inputPoint("Enter point A as X Y: ");
      Point pointB = inputPoint("Enter point B as X Y: ");
      Point pointC = inputPoint("Enter point C as X Y: ");
      Triangle originalTriangle = new Triangle(pointA, pointB, pointC);
      inputXYShifts();
      Triangle shiftedTriangle = originalTriangle.shift(xShift, yShift);
      System.out.println();
      System.out.println(originalTriangle);
      System.out.println("has area " + originalTriangle.areaOfTriangle()
                         + ", perimeter " 
                         + originalTriangle.perimeterOfTriangle());
      System.out.println("and when shifted by X offset " + xShift
                         + " and Y offset " + yShift + ", gives");
      System.out.println(shiftedTriangle);
      break;

    // Rectangle.
    case 3:
      Point diag1End1 = inputPoint("Enter one corner as X Y: ");
      Point diag1End2 = inputPoint("Enter opposite corner as X Y: ");
      Rectangle originalRectangle = new Rectangle(diag1End1, diag1End2);
      inputXYShifts();
      Rectangle shiftedRectangle = originalRectangle.shift(xShift, yShift);
      System.out.println();
      System.out.println(originalRectangle);
      System.out.println("has area " + originalRectangle.areaOfRectangle()
                         + ", perimeter " 
                         + originalRectangle.perimeterOfRectangle());
      System.out.println("and when shifted by X offset " + xShift
                         + " and Y offset " + yShift + ", gives");
      System.out.println(shiftedRectangle);
      break;

    // Bad choice.
    default:
      System.out.println("That wasn't 1, 2 or 3!");
      break;
  } // switch
} // main

} // class ShapeShift

除了ShapeShift类之外，所有类都编译。

我收到以下3个错误：

ShapeShift.java:78: error: cannot find symbol
        Circle shiftedCircle = originalCircle.shift(xShift, yShift);
 symbol:   method shift(double,double)

ShapeShift.java:96: error: cannot find symbol
        Triangle shiftedTriangle = originalTriangle.shift(xShift, yShift);
 symbol:   method shift(double,double)

ShapeShift.java:113: error: cannot find symbol
        Rectangle shiftedRectangle = originalRectangle.shift(xShift, yShift);
 symbol:   method shift(double,double)

我一直盯着这看了很久，真的很欣赏一双清新的眼睛。提前感谢任何可以提供帮助的人！

Answer 1

您在以下课程shift()，Circle和Triangle中没有Rectangle方法。

Answer 2

只有您的Point班级有shift方法。 Circle，Triangle和Rectangle没有。

Answer 3

正如我所看到的，问题是，您尚未在shift，Rectangle和Triangle类中声明任何名为Circle的方法，但您正在尝试叫它。

我能看到的唯一shift方法是Point类。

尝试编译时出现Java错误

3 个答案: