Extract All Digits From A String

Sometimes we may need to extract only digits from a string.

For example,
When we display a phone number we display as 001-00-100-200, some thing like that.
but when we save this number is a database as integer, then we need to remove hyphen and other characters.

In such situation we can use this following function.
 
 

CString GetAllDigits(LPCSTR lpTxt)
{
    CString csDigits;
    for(;*lpTxt!='\0'; lpTxt++)
    {
        if(*lpTxt>=48 && *lpTxt <58)
        {
            csDigits += *lpTxt;
        }
    }
    return csDigits;
}