Question

一道C#题目，急求答案！

用c#设计一个圆球的类，具有求体积和面积的方法，并前main创建一个半径为5的实例，输出体积面积

Answer 1

public class Ball
{
double _radius;
public Ball(double radius)
{
_radius=radius ;
}
public double GetCover() //面积
{
return 4 * Math.PI * _radius * _radius;
}
public double GetBulk() //体积
{
return 4 * Math.PI * _radius * _radius*_radius / 3;
}
}

static Main() //main 方法
{
Ball ball = new Ball(5);
Console.WriteLine(ball.GetCover().ToString());
}

Answer 2

class Program
{
static void Main(string[] args)
{
Ball ball = new Ball(5);
Console.WriteLine(ball.getArea());
Console.WriteLine(ball.getVolume());
}
}

public class Ball
{
private double _radius;

public Ball(double R)
{
this._radius = R;
}

public double getArea()
{
return 4.0 * Math.PI * Math.Pow(_radius, 2);
}
public double getVolume()
{
return 4.0 / 3.0 * Math.PI * Math.Pow(_radius, 3);
}
}

Answer 3

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;

namespace ConsoleApplication2
{
public class Ball
{
protected double r;

public double Radius
{
get
{
return r;
}
set
{
if (value < 0)
throw new Exception("Out of range!");
r = value;
}
}

public Ball()
{
this.r = 10;
}

public Ball(double r)
{
this.Radius = r;
}

public double area()
{
return 4 * Math.PI * Radius * Radius;
}

public double volume()
{
return 4 * Math.PI * Radius * Radius * Radius / 3;
}
}

class Program
{
static void Main(string[] args)
{
Ball instance = new Ball(5);
Console.WriteLine("Area:{0}", instance.area());
Console.WriteLine("volume:{0}", instance.volume());
}
}
}