java - 尺寸比较(周长/平方周长)等

Question

3个不同的类 1个用于处理Circle实例，1个用于Square实例，第3个用于比较之间他们(main) 。在 main 函数中，我找到了 circle (在 c1..c4 之间)和 square (在 s1...s5)并分别打印它们的最大周长和面积。[因此圆与圆和方与方的比较]

<强>!!!注意:只有半径或边长较大的周长或面积最大，所以我只使用 r 和 a 进行比较。我不知道如果我使用area/circumference方法是否可以返回this(不，因为那么我只会处理数字？) .请纠正我。

现在我想打印具有最大周长的几何形状(圆形/正方形)的特征(x，y，r/a)。我怎样才能做到这一点 ？在哪里比较？新类(class)？[方圆比较]

public class Circle {
        public double x,y,r;
        public double circumference() {
            return 2*(3.14)*r;
        }
        public double area() {
            return 3.14*r*r;
        }
        public Circle bigger(Circle c){
            if(c.r>r) return c; else return this; 
        } 
        public Circle(double x, double y, double r) {
            this.x=x; 
            this.y=y; 
            this.r=r;
        }
    }

public class Square {
    public double x,y,a;
    public double perimeter() {
        return 4*a;
    }
    public double area() {
        return a*a;
    }
    public Square bigger(Square s){
        if(s.a>a) return s; else return this; 
    } 
    public Square(double x, double y, double a) {
        this.x=x; 
        this.y=y; 
        this.a=a;
    }
}

public class CircleAndSquareTest {

    public static void main(String[] args) {
        Circle c1 = new Circle(0.0,0.0,1.0);
        Circle c2 = new Circle(1.0,0.0,2.0);
        Circle c3 = new Circle(0.0,2.0,4.0);
        Circle c4 = new Circle(1.0,3.0,1.0);
        Circle cb = c1.bigger(c2).bigger(c3).bigger(c4);
        System.out.println("The circle with the biggest circumference has:\n");
        System.out.println("x-axis value: " + cb.x + " y-axis value: " + cb.y + " radius: " + cb.r+"\n");

        Square s1 = new Square(0.0,0.0,1.0);
        Square s2 = new Square(0.0,0.0,1.0);
        Square s3 = new Square(0.0,0.0,5.0);
        Square s4 = new Square(4.0,2.0,2.0);
        Square s5 = new Square(0.0,0.0,1.0);
        Square sb = s1.bigger(s2).bigger(s3).bigger(s4).bigger(s5);
        System.out.println("The square with the biggest area has:\n");
        System.out.println("x-axis value: " + sb.x + " y-axis value: " + 
        sb.y + " side: " + sb.a);
    }
}

Answer 1

以下是如何使用比较器和 Collections 类来查找最大值。这尚未经过测试，但它应该可以满足您的要求。请注意，我在这里使用静态内部类，但如果需要，它们可以是在自己的文件中定义的标准类 - 这只是为了创建快速答案。

public interface Shape {
    double getPerimeter();
    double getArea();
}

public static class PerimeterComparator implements Comparator<Shape> {
    @Override
    public int compare(Shape a, Shape b) {
        return Double.compare(a.getPerimeter(), b.getPerimeter());
    }
}

public static class AreaComparator implements Comparator<Shape> {
    @Override
    public int compare(Shape a, Shape b) {
        return Double.compare(a.getArea(), b.getArea());
    }
}

public static class Circle implements Shape {
    private final double x, y, r;

    @Override
    public double getPerimeter() {
        return 2 * (3.14) * r;
    }

    @Override
    public double getArea() {
        return 3.14 * r * r;
    }

    public Circle(double x, double y, double r) {
        this.x = x;
        this.y = y;
        this.r = r;
    }

    public double getX() {
        return x;
    }

    public double getY() {
        return y;
    }

    public double getR() {
        return r;
    }
}

public static class Square implements Shape{
    private final double x, y, a;

    @Override
    public double getPerimeter() {
        return 4 * a;
    }

    @Override
    public double getArea() {
        return a * a;
    }

    public Square(double x, double y, double a) {
        this.x = x;
        this.y = y;
        this.a = a;
    }

    public double getX() {
        return x;
    }

    public double getY() {
        return y;
    }

    public double getA() {
        return a;
    }
}


public static void main(String[] args) {
    List<Shape> shapes = new ArrayList<>();
    List<Circle> circles = new ArrayList<>();
    circles.add(new Circle(0.0,0.0,1.0));
    circles.add(new Circle(1.0,0.0,2.0));
    circles.add(new Circle(0.0,2.0,4.0));
    circles.add(new Circle(1.0,3.0,1.0));

    Circle largestCircle = Collections.max(circles, new PerimeterComparator());

    System.out.println("The circle with the biggest circumference has:\n");
    System.out.println("x-axis value: " + largestCircle.getX() + " y-axis value: " + largestCircle.getY() + " radius: " + largestCircle.getPerimeter() +"\n");

    List<Square> squares = new ArrayList<>();
    squares.add(new Square(0.0,0.0,1.0));
    squares.add(new Square(0.0,0.0,1.0));
    squares.add(new Square(0.0,0.0,5.0));
    squares.add(new Square(4.0,2.0,2.0));
    squares.add(new Square(0.0,0.0,1.0));

    Square largestSquare = Collections.max(squares, new PerimeterComparator());

    System.out.println("The square with the biggest area has:\n");
    System.out.println("x-axis value: " + largestSquare.getX() + " y-axis value: " + largestSquare.getY() + " side: " + largestSquare.getA());

    shapes.addAll(circles);
    shapes.addAll(squares);

    Shape largestPerimeter = Collections.max(shapes, new PerimeterComparator());
    Shape largestArea      = Collections.max(shapes, new AreaComparator());

    System.out.printf("\nThe shape with the biggest perimeter is a %s and has has: a perimeter of: %f\n", largestPerimeter.getClass().getSimpleName(), largestPerimeter.getPerimeter());
    System.out.printf("The shape with the biggest area is a %s and has has: an area of: %f\n", largestArea.getClass().getSimpleName(), largestArea.getArea());
}