BASICBASIC functionsnum() function

num() function

The num() function evaluates an expression and returns 1 (true) if it is a decimal numeric. Otherwise, it returns 0, if the expression contains any nonnumeric characters.

Syntax

num(exp)

Parameter(s)

exp Expression to test. If it is a decimal numeric, 1 (true) is returned. If it contains any nonnumeric characters, 0 is returned.

Description

The empty, or null string ("") is considered to be a numeric string.

The strings below are considered to be numeric, and return a 1:

  • . (period)

  • - (minus)

  • + (plus)

  • -. (minus/period)

  • +. (plus/period)

Example(s)

This loop terminates when a numeric response is entered for the variable number.

loop
input number
until num(number) do repeat

See also

alpha() function, Boolean evaluation, BASIC functions, match relational operator, Statements and functions

Parent topic: BASIC functions