' FACTORING PROGRAM
'
' This program displays all the prime numbers
' under 1000, and then it lists the factors
' of all numbers between 6 and 1000.
'
' Written by Zsolt Nagy-Perge in December 2000.
' <zsnp500@cox.net>
'
DEFINT A-Z

CONST MAXVALUE = 1000    ' numbers to factor
DIM P(1 TO MAXVALUE)     ' products

CLS
PRINT "PRIME NUMBERS:"
PRINT

' Factor all numbers.
FOR I = 6 TO MAXVALUE
    FOR L = 2 TO MAXVALUE
        IF I * L > MAXVALUE THEN EXIT FOR
        P(I * L) = P(I * L) + 1
    NEXT L
NEXT I

' Print prime numbers.
FOR I = 1 TO MAXVALUE
    IF P(I) < 2 THEN PRINT LTRIM$(STR$(I)); CHR$(9);
NEXT I

PRINT
PRINT "PRESS ENTER TO CONTINUE...";
LINE INPUT L$

' Print factors for all numbers.
FOR A = 1 TO MAXVALUE
    N = A
    PRINT LTRIM$(STR$(N)) + CHR$(9); "=";
    FOR I = 2 TO N
   
        ' Divide N by its prime factors.
        IF P(I) < 2 THEN
        DO WHILE (N MOD I) = 0
            PRINT I;
            IF I < N THEN PRINT "x";
            N = N / I
        LOOP
        END IF
    NEXT I
    PRINT
NEXT A