计算圆面积和周长

[java]代码库

class Maths{
	double r;
	double girth;
	double area;
	final double PI=3.14;
	public void setR(double r) {
		this.r=r;
	}
	public double getR() {
		return r;
	}
	public void girth() {
		girth=2*PI*r;
		System.out.println("这个圆的周长是:"+girth);
	}
	public void area() {
		area=PI*r*r;
		System.out.println("这个圆的面积是:"+area);
	}
}

public class Main {
  public static void main(String[] args){
	 Maths maths=new Maths();
	 maths.setR(5.66);
	 maths.girth();
	 maths.area();
			  
  }
}