C#-get/set和方法重载

/*
属性的应用。
*/
using System;
using System.Collections.Generic;
using System.Collections;
using System.Linq;
using System.Text;

namespace ConsoleApplication2
{
class Program
{
static void Main(string[] args)
{
CircleArea cl=new CircleArea();
cl.Radius = double.Parse(Console.ReadLine());
Console.WriteLine(cl.GetArea());
Console.ReadKey();
}
}
class CircleArea{
private double radius;
const double PI=3.14;
public double Radius{
get{return radius;}
set{
if(value >0)
radius=value;
else
Console.WriteLine("overflow error!");
}
}
public double GetArea(){
return PI*radius*radius;
}
}
}

/*
编写一个名为MyClass的类，在该类中编写一个方法，名称为CountChar，返回值为整型，参数有两个，第一个参数可以是字符串、
整数、单精度、双精度，第二个参数为字符，方法功能返回第二个参数在第一个参数中出现的次数。
例如：，CountChar("6221982",'2')返回值为3。
*/
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;

namespace ConsoleApplication2
{
class Program
{
static void Main(string[] args)
{
Console.WriteLine("出现次数为：{0}",MyClass.CountChar("6221982", '2'));
Console.WriteLine("出现次数为：{0}", MyClass.CountChar(629.2223, '2'));
Console.WriteLine("出现次数为：{0}", MyClass.CountChar(45652332, '2'));
Console.WriteLine("出现次数为：{0}", MyClass.CountChar("6221982", '2'));
Console.ReadKey();
}

}
class MyClass
{
public static int CountChar(string s, char c)
{
int count = 0;
char[] a = s.ToCharArray();
for (int i = 0; i < a.Length; i++)
{
if (a[i] == c)
count++;
}
return count;
}
public static int CountChar(float s, char c)
{
int count = 0;
char[] a = s.ToString().ToCharArray();
for (int i = 0; i < a.Length; i++)
{
if (a[i] == c)
count++;
}
return count;
}
public static int CountChar(int s, char c)
{
int count = 0;
char[] a = s.ToString().ToCharArray();
for (int i = 0; i < a.Length; i++)
{
if (a[i] == c)
count++;
}
return count;
}
public static int CountChar(double s, char c)
{
int count = 0;
char[] a = s.ToString().ToCharArray();
for (int i = 0; i < a.Length; i++)
{
if (a[i] == c)
count++;
}
return count;
}
}
}