round.java

加密解密技巧

package zuoye.entity;

public class Round extends Shape {
	private final double PI = 3.14;
	private double r;
	
	public Round(double r) {
		super();
		this.r = r;
	}
	public Round() {
		super();
		// TODO Auto-generated constructor stub
	}
	public double girth(){// 2 PI r
		return 2*PI*r;
	}
	public void area(){//PI r*r
		System.out.println(PI*r*r);
	}
}