【发布时间】：2017-11-08 18:51:43
【问题描述】：
我有这个程序，它应该使用它的类型（矩形、三角形、圆形）和它的尺寸（长度/宽度、底边/高度、半径）将形状添加到数组中。它还应该能够从数组中删除一个形状。目前，我可以向数组添加一个形状，但是当我尝试删除它时（基于形状类型和面积，而不是形状类型和尺寸），它会打印出找不到形状。
示例：我添加了一个长度为 3 和宽度为 2 的矩形。它的面积是 6。当我尝试删除一个面积为 6 的矩形时，它不会从数组中删除这个矩形，因为它应该不能找到它。
为了澄清，主要问题出在前端的 removeAShapeDialogue 部分和代码的 Collection 部分的 removeShape 方法。
注意事项：
- 形状是一个界面
- 我无法按照指令创建任何其他类、方法或接口，因此必须有使用此处的任何内容的解决方案。
- 我认为问题不在于 Rectangle、Triangle 或 Circle 类
- 我也遇到了 ShapeCollection 类中的选择排序问题，因此我们将不胜感激。
前端
import java.util.Scanner;
public class ShapeFrontEnd {
public static void main(String[] args) {
Scanner keyboard = new Scanner(System.in);
System.out.println("Welcome to the Shapes Collection.");
ShapeCollection shapes = new ShapeCollection();//New instance of ShapeCollection
boolean quit = false;
while(!quit)//Runs until quits
{
printOptions();
int pick = keyboard.nextInt();
keyboard.nextLine();
switch(pick)
{
case 1://Add shape
shapes.addShape(makeAShapeDialogue());
break;
case 2://Remove shape
shapes.removeShape(removeAShapeDialogue());
break;
case 9://Quit
quit = true;
System.out.println("Goodbye");
System.exit(0);
break;
default:
System.out.println("Invalid input.");
}
System.out.println("Current Shapes:");
shapes.printShapes(shapes);
}
}
//Helper Methods
public static void printOptions()//Prints user's input options
{
System.out.println("Enter 1: Add a shape\nEnter 2: Remove a shape\nEnter 9: Quit");
}
public static Shape makeAShapeDialogue()//Prints the dialogue after user enters "1"
{
Scanner keyboard = new Scanner(System.in);
Shape newShape;
System.out.println("What type of shape? Rectangle, Triangle, or Circle?");
String shapeType = keyboard.nextLine();
if(shapeType.equalsIgnoreCase("rectangle"))
{
System.out.println("Enter length.");
double length = keyboard.nextDouble();
System.out.println("Enter height.");
double height = keyboard.nextDouble();
keyboard.nextLine();
newShape = new Rectangle(length, height);
}
else if(shapeType.equalsIgnoreCase("triangle"))
{
System.out.println("Enter base.");
double base = keyboard.nextDouble();
System.out.println("Enter height.");
double height = keyboard.nextDouble();
keyboard.nextLine();
newShape = new Triangle(base, height);
}
else if(shapeType.equalsIgnoreCase("circle"))
{
System.out.println("Enter radius.");
double radius = keyboard.nextDouble();
keyboard.nextLine();
newShape = new Circle(radius);
}
else
{
newShape = null;
}
return newShape;
}
public static Shape removeAShapeDialogue()
{
ShapeCollection shapes = new ShapeCollection();
Scanner keyboard = new Scanner(System.in);
Shape newShape;
System.out.println("What type of shape? Rectangle, Triangle, or Circle?");
String shapeType = keyboard.nextLine();
System.out.println("Enter area.");
double area = keyboard.nextDouble();
keyboard.nextLine();
if(shapeType.equalsIgnoreCase("rectangle"))
{
newShape = new Rectangle();
}
if(shapeType.equalsIgnoreCase("triangle"))
{
newShape = new Triangle();
}
if(shapeType.equalsIgnoreCase("circle"))
{
newShape = new Circle();
}
else
{
newShape = null;
}
return newShape;
}
}
集合/数组类
public class ShapeCollection {
private Shape[] shapes;
public static final int MAX_SHAPES = 5;
//Constructor
public ShapeCollection()
{
shapes = new Shape[MAX_SHAPES];
}
//Method to get all the Shapes
public Shape[] getShapes()
{
return this.shapes;
}
//Add Shape
public void addShape(Shape aShape)
{
for(int i=0;i<shapes.length;i++)
{
if(shapes[i] == null)
{
shapes[i] = aShape;
return;
}
}
System.out.println("You cannot fit any more shapes.");
}
//Remove Shape
public void removeShape(Shape aShape)
//public void removeShape(String aShapeType, double anArea)
{
for(int i=0;i<shapes.length;i++)
{
System.out.println(shapes[i]);
if(shapes[i] != null && shapes[i].equals(aShape))
//if(shapes[i] != null && shapes[i].getType().equals(aShapeType) && shapes[i].getArea() == (anArea))
{
shapes[i] = null;
return;
}
}
System.out.println("Cannot find that shape.");
}
//Sort Shapes
private void sortShapes()
{
for(int i=0;i<shapes.length-1;i++)
{
int smallestIndex = i;
for(int j=i+1; j<shapes.length;j++)
{
if(shapes[j].getArea() < shapes[smallestIndex].getArea())
{
smallestIndex = j;
}
/*if(smallestIndex !=i)
{
Shape number = shapes[i];
shapes[i] = shapes[smallestIndex];
shapes[smallestIndex] = number;
}*/
}
Shape temp = shapes[smallestIndex];
shapes[smallestIndex] = shapes[i];
shapes[i] = temp;
}
}
//Prints Shapes
public void printShapes(ShapeCollection shapeC)
{
//sortShapes();
for(Shape s : shapeC.getShapes())
{
if(s == null)
continue;
System.out.println(s);
System.out.println();
}
}
}
形状界面
public interface Shape {
public double getArea();
public String toString();
public String getType();
}
矩形类
public class Rectangle implements Shape{
//Attributes
private double length;
private double width;
//Constructors
public Rectangle()//Default
{
this.length = 0.0;
this.width = 0.0;
}
public Rectangle(double aLength, double aWidth)//Parameterized
{
this.setLength(aLength);
this.setWidth(aWidth);
}
//Accessors
public double getLength()
{
return this.length;
}
public double getWidth()
{
return this.width;
}
//Mutators
public void setLength(double aLength)
{
if(aLength>0)
{
this.length = aLength;
}
else
{
System.out.println("Invalid length.");
}
}
public void setWidth(double aWidth)
{
if(aWidth>0)
{
this.width = aWidth;
}
else
{
System.out.println("Invalid width.");
}
}
//Other Methods
public double getArea()
{
return this.length*this.width;
}
public String getType()
{
return "RECTANGLE";
}
public String toString()
{
return getType() + " | Length: " + this.length + " | Width: " + this.width + " | Area: " + getArea();
}
}
三角形类
public class Triangle implements Shape{
//Attributes
private double base;
private double height;
//Constructors
public Triangle()
{
this.base = 0.0;
this.height = 0.0;
}
public Triangle(double aBase, double aHeight)
{
this.setBase(aBase);
this.setHeight(aHeight);
}
//Accessors
public double getBase()
{
return this.base;
}
public double getHeight()
{
return this.height;
}
//Mutators
public void setBase(double aBase)
{
if(aBase>0)
{
this.base = aBase;
}
else
{
System.out.println("Invalid base.");
}
}
public void setHeight(double aHeight)
{
if(aHeight>0)
{
this.height = aHeight;
}
else
{
System.out.println("Invalid height.");
}
}
//Other Methods
public double getArea()
{
return (this.base*this.height)/2;
}
public String getType()
{
return "TRIANGLE";
}
public String toString()
{
return getType() + " | Base: " + this.base + " | Height: " + this.height + " | Area: " + getArea();
}
}
圆类
public class Circle implements Shape{
//Attributes
private double radius;
//Constructors
public Circle()
{
this.radius = 0.0;
}
public Circle(double aRadius)
{
this.setRadius(aRadius);
}
//Accessors
public double getRadius()
{
return this.radius;
}
//Mutators
public void setRadius(double aRadius)
{
if(aRadius>0)
{
this.radius = aRadius;
}
else
{
System.out.println("Invalid radius.");
}
}
//Other Methods
public double getArea()
{
return Math.PI*(radius*radius);
}
public String getType()
{
return "CIRCLE";
}
public String toString()
{
return getType() + " | Radius: " + this.radius + " | Area: " + getArea();
}
}
【问题讨论】：