– 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.com，在A中生成一个Cylinder对象，并输出其体积。编译并运行该类。
– 试着改变求体积方法的访问权限，查看并分析编译和运行结果
– 把Cylinder类和A类置于不同的包中，通过对求体积方法设置不同的访问权限，查看并分析编译和运行结果
package bzu.info.software;
public class Circle {
private double r;
public double getR() {
return r;
}
public void setR(double r) {
this.r = r;
}
}
package bzu.info.com;
import bzu.info.software.Circle;
public class Cylinder {
private Circle circle;
public Circle getCircle() {
return circle;
}
public void setCircle(Circle circle) {
this.circle = circle;
}
public double getHeight() {
return height;
}
public void setHeight(double height) {
this.height = height;
}
private double height;
}
package bzu.info.com;
import bzu.info.software.Circle;
public class TestA {
static Cylinder cylinder;
static Circle circle;
public static void main(String[] args) {
cylinder=new Cylinder();
circle=new Circle();
circle.setR(2);
cylinder.setCircle(circle);
cylinder.setHeight(7);
calV();
}
private static void calV() {
double vNum=3.14*circle.getR()*circle.getR()*cylinder.getHeight();
System.out.println("底面半径为"+circle.getR()+"，高为"+cylinder.getHeight()+"的圆柱体的体积为："+vNum);
}
}