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The 640 MEG Shareware Studio 2
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The 640 Meg Shareware Studio CD-ROM Volume II (Data Express)(1993).ISO
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basic
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qbfaqr01.zip
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ERATOS.BAS
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BASIC Source File
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1992-08-10
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774b
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41 lines
'Date: 03-23-92 (22:35)
'From: BRENT ASHLEY
'---------------------------------------------------------------------------
'Here's a variation on a program I entered in a primes contest about a
'year ago.
DEFINT A-Z
' initialise array to zeros
DIM flags(10000)
max = 10000
rootmax = SQR(max)
NonPrime = -1
' show 2 as prime
PRINT " 2 ";
' flag all non-primes
FOR Num = 3 TO rootmax STEP 2
' check for prime
IF NOT flags(Num) THEN
' print prime number
PRINT USING " ###### "; Num;
' flag all multiples
multiple = 2 * Num
WHILE multiple <= max
flags(multiple) = NonPrime
multiple = multiple + Num
WEND
END IF
' flag even numbers
flags(Num + 1) = NonPrime
NEXT
END ' of program