messagebox(iif(isPrime(2)=.t.,"质数","非质数"))
FUNCTION isPrime(n)
    LOCAL i
    IF n <= 3
        RETURN  n > 1
    ENDIF
    IF (n % 2 == 0) OR (n % 3 == 0)
         RETURN  .F.
    ENDIF
    i = 5
    DO WHILE i * i <= n
        IF (n % i == 0) OR (n % (i + 2) == 0) 
            RETURN .F.
        ENDIF
        i = i + 6
    ENDDO
    RETURN .T.
ENDFUNC