Remove formatting from a string: “(123) 456-7890” => “1234567890”?

Question

I have a string when a telephone number is inputted - there is a mask so it always looks like \"(123) 456-7890\" - I\'d like to take the formatting out before saving it to the D

Answer 1

Since nobody did a for loop.

long GetPhoneNumber(string PhoneNumberText)
{
    // Returns 0 on error

    StringBuilder TempPhoneNumber = new StringBuilder(PhoneNumberText.Length);
    for (int i=0;i

used like this:

long phoneNumber = GetPhoneNumber("(123) 456-7890"); 

Update
As pr commented many countries do have zero's in the begining of the number, if you need to support that, then you have to return a string not a long. To change my code to do that do the following:

1) Change function return type from long to string.
2) Make the function return null instead of 0 on error
3) On successfull parse make it return PhoneNumberText