定义一个圆，求圆的面积

逃离我推掉我的手 2022-04-06 08:51 295阅读 0赞

# 定义一个圆，求圆的面积 #

TestCircle .java

class Point {
        private double x;
        private double y;
        Point(double x1, double y1) { 
        	x = x1; 
        	y = y1;
        }
        public double getX() { return x; }
        public double getY() { return y; }
        public void setX(double i) { x = i; }
        public void setY(double i) { y = i; }
    }
    
    class Circle {
        private Point o;	//圆心
        private double radius;	//半径
        Circle(Point p, double r) {
        	o = p; 
        	radius = r;
        }
        Circle(double r) {
            o = new Point(0.0, 0.0);
            radius = r;
        }
        
        boolean contains(Point p) {
        	double x = p.getX() - o.getX();
        	double y = p.getY() - o.getY();
        	if(x*x + y*y > radius * radius) return false;
        	else return true;
        }
        
        
        public void setO(double x, double y) {
            o.setX(x); 
            o.setY(y);
        }
        public Point getO() { return o; }
        public double getRadius() { return radius;}
        public void setRadius(double r) { radius = r;}
        public double area() { //求圆的面积
            return 3.14 * radius * radius;
        }
    }
    
    public class TestCircle {
        public static void main(String args[]) {
            Circle c1 = new Circle(new Point(1.0,2.0), 2.0);
            Circle c2 = new Circle(5.0);
            System.out.println("c1:("+c1.getO().getX()+","
                +c1.getO().getY()+"),"+c1.getRadius());	//c1:(1.0,2.0),2.0
            System.out.println("c2:("+c2.getO().getX()
                +","+c2.getO().getY()+"),"+c2.getRadius());//c2:(0.0,0.0),5.0
            System.out.println("c1 area = "+c1.area());//c1 area = 12.56
            System.out.println("c1 area = "+c2.area());//c1 area = 78.5
            c1.setO(5,6);
            c2.setRadius(9.0);
            System.out.println("c1:("+c1.getO().getX()+","
                +c1.getO().getY()+"),"+c1.getRadius());//c1:(5.0,6.0),2.0
            System.out.println("c2:("+c2.getO().getX()+","
                +c2.getO().getY()+"),"+c2.getRadius());//c2:(0.0,0.0),9.0
            System.out.println("c1 area = "+c1.area());//c1 area = 12.56
            System.out.println("c1 area = "+c2.area());//c1 area = 254.34
            
            Point p1 = new Point(5.2, 6.3);
            System.out.println(c1.contains(p1));//true
            System.out.println(c1.contains(new Point(10.0,9.0)));//false
            
        }
    }