Area of a Circle

Area of a Circle

Description:

Complete the function circleArea so that it will return the area of a circle with the given radius. Round the returned number to two decimal places (except for Haskell). If the radius is not positive or not a number, return false.

Example:

Kata.CalculateAreaOfCircle("-123"); //throws ArgumentException
Kata.CalculateAreaOfCircle("0"); //throws ArgumentException
Kata.CalculateAreaOfCircle("43.2673"); //return 5881.25
Kata.CalculateAreaOfCircle("68"); //return 14526.72
Kata.CalculateAreaOfCircle("number"); //throws ArgumentException

using System;

public static class Kata
{
  public static double CalculateAreaOfCircle(string radius)
  {   
    //Solve!
    try
            {
                //if (radius.IndexOf(',') != -1)
                if (radius.Contains(","))
                {
                    throw new ArgumentException();
                }
                double r = Convert.ToDouble(radius);
                if (r <= 0)
                {
                    throw new ArgumentException();
                }
                else
                {
                    return Convert.ToDouble((Math.PI * Math.Pow(r, 2)).ToString("f2"));
                }
            }
            catch
            {
                throw new ArgumentException();
            }
  }
}

其他人的解法：

使用Math.Round以及out参数  double的TryParse

using System;

public static class Kata
{
  public static double CalculateAreaOfCircle(string radius)
  {   
    double number;

    if (radius.Contains(",") || !double.TryParse(radius, out number) || double.TryParse(radius, out number) && number < 1)
    {
      throw new ArgumentException();
    }
    
    return Math.Round(number * number * Math.PI, 2);

  }
}