How can I generate text file with all the prime numbers in progress 4gl - progress-4gl

Question

In the below code i am importing a text file with numbers 3 to 99 .
i have partially written code to find out the prime numbers from the given numbers.
define variable a as integer.
define variable b as integer.
define variable i as integer initial 0.
INPUT FROM Value ( "C:\src\New folder\bingo.txt").
repeat :
IMPORT a.
b = a mod i.
if b=0 then
do:
if a=i then
do:
message " prime number"a view-as alert-box.
end.
else if a<>i then
do:
i=i + 1.
message " not prime number"a view-as alert-box.
end.
else if a < i then
do:
message "not prime number"a view-as alert-box.
end.
end.
END.
if b<>0 then
do:
i=i + 1.
message "b<>0"b view-as alert-box.
end.
end.
Output To Value( "C:\src\New folder\even.txt")append.
export a space.
output close.
end.
end.
help me with .
to program

Answer 1

I think it will make more sense to store the prime check in a function or a procedure. This prime check isn't necessary perfect but it will work for these conditions.
Also it's best to define and use streams when working with both in- and output.
DEFINE VARIABLE a AS INTEGER NO-UNDO.
DEFINE VARIABLE b AS INTEGER NO-UNDO.
DEFINE STREAM strIn.
DEFINE STREAM strOut.
FUNCTION isPrime RETURNS LOGICAL (INPUT iNum AS INTEGER ):
DEFINE VARIABLE iDiv AS INTEGER NO-UNDO.
DO iDiv = 2 TO INTEGER(SQRT(iNum)):
IF iNum MOD iDiv = 0 THEN
RETURN FALSE.
END.
RETURN TRUE.
END.
OUTPUT STREAM strOut TO VALUE ("c:\temp\primes.txt").
INPUT STREAM strIn FROM Value ( "C:\temp\bingo.txt").
repeat :
IMPORT STREAM strIn a.
IF isPrime(a) THEN DO:
/*MESSAGE "prime number" a view-as alert-box. */
PUT STREAM strOut UNFORMATTED a SKIP.
END.
ELSE DO:
/*MESSAGE "not prime number" a view-as alert-box. */
END.
END.
INPUT STREAM strIn CLOSE.
OUTPUT STREAM strOut CLOSE.