XLISP evenp

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# evenp

Type: | - | predicate function (subr)
Source: | - | xlmath.c

## Syntax

(evenp expr)
  expr - the integer numeric expression to check
  returns - T if the integer is even, NIL otherwise

## Description

The 'evenp' predicate function checks to see if the number 'expr' is even. T is returned if the number is even, NIL is returned otherwise.

An error is generated if the 'expr' is not a numeric expression:

    error: bad argument type

An error is generated if the 'expr' is a floating point number:

    error: bad floating point operation

Zero is an even number.

## Examples

    (evenp 0)     ; returns T
    (evenp 1)     ; returns NIL
    (evenp 2)     ; returns T
    (evenp -1)    ; returns NIL
    (evenp -2)    ; returns T
    (evenp 14.0)  ; error: bad floating point operation
    (evenp 'a)    ; error: bad argument type
    (setq a 2)    ; set value of A to 2
    (evenp a)     ; returns T

See the evenp predicate function in the XLISP 2.0 manual.

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Nyquist / XLISP 2.0 - Contents | Tutorials | Examples | Reference