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(); |
|
} |
} |