FACT()

Calculates faculty

Syntax

      FACT( <nNumber> ) -> nFaculty

Arguments

<nNumber> number between 0 and 21

Returns

<nFaculty> the faculty of <nNumber>

Description

The function FACT() calculates the faculty to the integer given in <nNumber>. The faculty is defined as n! = 1*2*…*n and is often used in statistics. Note, that faculties above 21 are too big so that the function must return a -1.

Examples

      ? fact( 0 ) // --> 1
      ? fact( 1 ) // --> 1
      ? fact( 4 ) // --> 24

Tests

      fact( 0 ) == 1
      fact( 1 ) == 1
      fact( 4 ) == 24

Compliance

FACT() is compatible with CT3’s FACT().

Platforms

All

Files

Source is math.c, library is libct.