testcircle.java

我在学习JAVA的讲义

class Circle{
	private double radius;
	public void setRadius(double r) {
		radius = r;
	}
	public double getArea() {
		return Math.PI * radius * radius;
	}
	public double getPerimenter() {
		return 2 * Math.PI * radius;
	}
	public double getRadius() {
		return radius;
	}
}

public class TestCircle {
	public static void main(String[] args) {
		Circle r1 = new Circle();
		r1.setRadius(3);
		System.out.println("Radius = " + r1.getRadius());
		System.out.println("Area = " + r1.getArea());
		System.out.println("Perimenter = " + r1.getPerimenter());
	}
}