[playbox12]

You could simply use the stock IsNumeric, to determine if the string is completely numeric, if it returns false, there are characters or letters in it.

Usage;
if(!IsNumeric(string))

pawn Код:

stock IsNumeric(str[])
{
    new ch, i;
    while ((ch = str[i++])) if (ch < '0' || ch > '9') return 0;
    return 1;
}

EDIT: Beaten twice in a row, both of you good job. I seriously need to refresh before posting.