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Static variables can be shared by all instances of a class, so static variables can be used as shared data between instances to increase interactivity between instances.
If all instances of a class contain the same constant property, you can define this property as a static constant type to save memory space. For example, define a static constant PI in the class.
[Problem Description] Define three classes Circle, Cylinder and main class, pi = 3.14
Circle class:
attributes:
double radius;
double area;
methods are:
Circle (double radius), construction method of Circle class.
double getArea(), calculates the circle area.
Cylinder class:
Attributes:
Circle bottom;
double height;
Method:
Cylinder (Circle bottom, double height), the construction method of the Cylinder class.
double getVolme(), calculates the volume of the cylinder.
Main class:
Input circle radius and cylinder height, and output cylinder volume.
[Input form] Please enter the radius of the base circle. If the radius is less than 0, set the radius to 0.
请输入圆柱体的高。如果高小于0，就将高设为0。
[Output form] Find the volume of the cylinder.
[Sample input 1]
please input the radius of the circle
-2
The radius is not less than 0.
please input the height of the cylinder
3
[Sample input 1]
The volume is: 0.0
[Sample input 2]
please input the radius of the circle
5
please input the height of the cylinder
-3
The height is not less than 0.
[Sample output 2]
The volume is: 0.0
[Sample input 3]
please input the radius of the circle
2
please input the height of the cylinder
3
import java.util.Scanner;
class Circle{
double radius;
double area;
Circle(double radius) {
if (radius<0)
{
System.out.println("The radius is not less than 0.");
this.radius=0;
}
else{
this.radius=radius;
}
}
double getArea(){
area=3.14*radius*radius;
return area;
}
}
class Cylinder{
Circle bottom;
double height;
Cylinder(Circle bottom, double height)
{
if (height<0)
{
System.out.println("The height is not less than 0.");
this.height=0;
this.bottom=bottom;
}
else{
this.bottom=bottom;
this.height=height;
}
}
double getVolme(){
return bottom.getArea()*height;
}
}
public class yuanzhu {
public static void main(String[] args) {
Scanner in=new Scanner(System.in);
System.out.println("please input the radius of the circle");
double radius=in.nextDouble();
Circle x=new Circle(radius);
System.out.println("please input the height of the cylinder");
double height=in.nextDouble();
Cylinder y=new Cylinder