–定义一个圆类(Circle)，其所在的包为bzu.info.software；定义一个圆柱类Cylinder，其所在的包为bzu.info.com；定义一个主类A，其所在的包也为bzu.info.

package bzu.info.software;


public class Circle {

public double radius;

public void setR(double r){
this.radius = r;
}

public double getS(){
return radius*radius*3.14;
}

}

package bzu.info.com;


import bzu.info.software.Circle;


public class Cylinder {
Circle circle;
double h;

void setH(double h){
this.h = h;
}

void setR(Circle c){
this.circle = c;
}

void show(){
System.out.println("体积为"+circle.getS()*h);
}


}

package bzu.info.com;


import bzu.info.software.Circle;


public class A {


public static void main(String[] args) {
Circle c = new Circle();
c.setR(3.1);
Cylinder cy = new Cylinder();
cy.setR(c);
cy.setH(2.3);
cy.show();


}


}