circle.java

本源码主要是上课时所做实验

class Cir
{
 private int r;
 public  float PI=3.14f;
     Cir()
    {
     r=5;
    }
   Cir(int n)
   {
     r=n;
   }
   Cir(Cir b)
   {
     r=b.r();
   }
  int r()
  {
  return r;
  }
  float sq()
  { 
  float s;
   s=PI*r*r;
    return s;
}
  float c()
 {
  float c;
 c=2*PI*r;
 return c;
}
}
public class Circle

{

    public static void main(String args[ ])

    {
        Cir x1=new Cir();
        Cir x2=new Cir(10);
        Cir x3=new Cir(x1);
        System.out.println(x1.sq());
        System.out.println(x1.c());
        System.out.println(x2.r());
        System.out.println(x2.sq());
        System.out.println(x3.c());
        System.out.println(x3.sq());
}
}