Adding two numbers

[mayundo]

Can anyone tell me what's wrong with this code?

using System;
using System.IO;

class Program
{
static void Main()
{
StreamReader sr = new StreamReader(Console.OpenStandardInput());
string str = sr.ReadToEnd();
int numb = 0, result = 0, len = str.Length;

    for (int i = 0; i < len; i++)
    {
        if (str[i] >= '0' && str[i] <= '9')
            numb = numb * 10 + (str[i] - 48);
        else if (str[i] == '\r')
        {
            result += numb;
            numb = 0;
        }
    }

    Console.WriteLine(result.ToString());
}

}

[TripleM_sof]

Have you tested your code on the largest possible inputs?

[mayundo]

I tested it on the 'Adding two numbers' input and it doesn't work.

[TripleM_sof]

What do you mean? If you have found case for which it doesn't work (eg the one I mentioned), then you should know how to fix it.