How To Determine Whether a Number is Prime

• 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
• Professional Edition of Microsoft Visual FoxPro for Macintosh, version 3.0

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