Q153200: How To Determine Whether a Number is Prime

Article: Q153200
Product(s): Microsoft FoxPro
Version(s): MACINTOSH:2.5b,2.5c,2.6a; MS-DOS:2.0,2.5,2.5a,2.5b,2.6,2.6a; UNIX:2.6; WINDOWS:3.0,3.0b
Operating System(s): 
Keyword(s): 
Last Modified: 15-DEC-1999

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The information in this article applies to:

- Microsoft Visual FoxPro for Windows, versions 3.0, 3.0b 
- Microsoft FoxPro for Macintosh, versions 2.5b, 2.5c, 2.6a 
- Microsoft FoxPro for MS-DOS, versions 2.0, 2.5, 2.5a, 2.5b, 2.6, 2.6a 
- Microsoft FoxPro for UNIX, version 2.6 
- Microsoft Visual FoxPro for Macintosh, Professional Edition, version 3.0 
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SUMMARY
=======

There is no single function in FoxPro or Visual FoxPro that determines whether a
number is prime. This article describes how to use a program that allows you to
enter a positive number and then reports if that number is prime.

MORE INFORMATION
================

A prime number is a number divisible only by one and itself. The following
program uses the MOD()and ABS() functions along with a For...Next loop to check
if a number is prime:

     CLEAR
     SET TALK OFF
     x=0
     @ 1,10 SAY "Please enter a positive integer"  GET x
     READ
     x=ABS(x)
     FOR i=2 to x-1
        IF MOD(x,i)=0
            @2,10 SAY  "The number "+ ALLTRIM(STR(x))+ " is not prime."
            RETURN
        ENDIF
     ENDFOR
     @ 2,10 SAY "The number "+ ALLTRIM(STR(x))+ " is prime."
     SET TALK ON

While this program uses the READ statement for backward compatibility with FoxPro
2.x versions, the basic algorithm may be used in a form within Visual FoxPro.

Additional query words: VFoxWin VFoxMac

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Keywords          :  
Technology        : kbHWMAC kbOSMAC kbVFPsearch kbAudDeveloper kbFoxproSearch kbZNotKeyword3 kbFoxPro250bMac kbFoxPro260aMac kbFoxPro250cMac kbFoxPro200DOS kbFoxPro250DOS kbFoxPro250aDOS kbFoxPro250bDOS kbFoxPro260DOS kbFoxPro260aDOS kbFoxPro260UNIX kbVFP300Mac kbVFP300 kbVFP300b
Version           : MACINTOSH:2.5b,2.5c,2.6a; MS-DOS:2.0,2.5,2.5a,2.5b,2.6,2.6a; UNIX:2.6; WINDOWS:3.0,3.0b; :3.0

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