strnatstring to natural number function

Syntax   strnat ( s : string [ , base : int ] ) : nat

Description   The strnat function is used to convert a string to a natural number. The natural number is equivalent to string s. The number base parameter is optional, for example, strnat("47") = 47.

String s must consist of a possibly null sequence of blanks, then an optional plus sign, and finally a sequence of one or more digits. For number bases larger than 10, the digits can include a, b, c (alternately A, B, C ) which represent the digit values 10, 11, 12 The base, if given, must be in the range 2 to 36 (36 because there are 10 base ten digits and 26 letters). For example, strnat("FF", 16) = 255.

The natstr function is the inverse of strnat, so for any natural number n, strnat( natstr (n)) = n.

The strnat function is similar to strint, except that strnat handles values that are larger than int values and does not handle negative values.

See also   the chr, ord, intstr and strint functions.