public class Circle {
private double radius;
public double getRadius() {
return radius;
}
public void setRadius(double radius) {
this.radius = radius;
}
}
public class Ball extends Circle{
public double Area(){
return this.getRadius()*this.getRadius()*4*3.1415926;
}
public double Area2(){
return (4/3)*3.1415926*this.getRadius()*this.getRadius()*this.getRadius();
}
}```
```java
public class Main {
public static void main(String []args){
Ball ball = new Ball();
ball.setRadius(4.13);
System.out.println(ball.Area());
System.out.println(ball.Area2());
}
}
#pragma once
using namespace std;
class circle {
private:
double radius;
public:
circle();
~circle();
double area();
double area2();
double getRadius();
void setRadius(double radiusOne);
};```
```cpp
#include "circle.h"
circle::circle() {}
circle::~circle(){}
//静态成员
double circle::getRadius() {
return radius;
}
void circle::setRadius(double radiusOne) {
radius = radiusOne;
}```
```cpp
#pragma once
#include "circle.h"
class ball :public circle
{
public:
virtual double area();
virtual double area2();
};```
```cpp
#include "ball.h"
double ball::area() {
return getRadius() * getRadius() * 4 * 3.1415926;
}
double ball::area2() {
return (4 / 3) * 3.1415926 * getRadius() * getRadius() * getRadius();
}```
```cpp
#include "ball.h"
#include
using namespace std;
int main() {
ball *one = new ball();
one->setRadius(4.17);
std::cout << one->getRadius() << std::endl;
std::cout << one->area() << std::endl;
std::cout << one->area2() << std::endl;
}```
