题目:
– 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
代码:
package bzu.info.com;
public class A {
public static void main(String[] args) {
// TODO Auto-generated method stub
Cylinder cylinder=new Cylinder(3,2);
System.out.println(cylinder.getvolume());
}
}
package bzu.info.com;
import bzu.info.software.*;//导入bzu中的所有类;import 导入,输入。//import java.util.*导入java内置所有类
public class Cylinder {
Circle bottom;
int height;
public Cylinder(Circle bottom, int height) {
this.bottom = bottom;
this.height = height;
}
public Cylinder(int r, int height) {
this.bottom = new Circle(r);
this.height = height;
}
public double getvolume() {
return height*bottom.getarea();
}
}
package bzu.info.com;
import bzu.info.software.*;//导入bzu中的所有类;import 导入,输入。//import java.util.*导入java内置所有类
public class Cylinder {
Circle bottom;
int height;
public Cylinder(Circle bottom, int height) {
this.bottom = bottom;
this.height = height;
}
public Cylinder(int r, int height) {
this.bottom = new Circle(r);
this.height = height;
}
public double getvolume() {
return height*bottom.getarea();
}
}
结果: