91 lines
2.6 KiB
Plaintext
91 lines
2.6 KiB
Plaintext
/*
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* File......: GCD.PRG
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* Author....: David Husnian
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* CIS ID....: ?
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*
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* This is an original work by David Husnian and is placed in the
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* public domain.
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*
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* Modification history:
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* ---------------------
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*
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* Rev 1.2 15 Aug 1991 23:03:40 GLENN
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* Forest Belt proofread/edited/cleaned up doc
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*
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* Rev 1.1 14 Jun 1991 19:51:56 GLENN
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* Minor edit to file header
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*
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* Rev 1.0 01 Apr 1991 01:01:26 GLENN
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* Nanforum Toolkit
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*
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*/
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/* $DOC$
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* $FUNCNAME$
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* FT_GCD()
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* $CATEGORY$
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* Math
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* $ONELINER$
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* Calculate greatest common divisor of two numbers
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* $SYNTAX$
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* FT_GCD( <nNumber1>, <nNumber2> ) -> nGCD
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* $ARGUMENTS$
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* <nNumber1> is the first number to find the GCD of.
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*
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* <nNumber2> is the second number to find the GCD of.
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* $RETURNS$
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* The greatest common divisor of the 2 numbers, or 0 if either is 0.
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* $DESCRIPTION$
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* This function calculates the greatest common divisor between 2 numbers,
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* i.e., the largest number that will divide into both numbers evenly. It
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* will return zero (0) if either number is zero.
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* $EXAMPLES$
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* ? FT_GCD(10,15) // Result: 5
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* ? FT_GCD(108,54) // Result: 54
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* ? FT_GCD(102,54) // Result: 6
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* ? FT_GCD(111,17) // Result: 1
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* $END$
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*/
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#command REPEAT ;
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=> ;
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DO WHILE .T.
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#command UNTIL <Condition> ;
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=> ;
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IF <Condition> ; EXIT ; END ; END
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#ifdef FT_TEST
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FUNCTION MAIN( cNum1, cNum2 )
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RETURN OUTSTD( STR(FT_GCD( val(cNum1), val(cNum2) )) + CHR(13) + CHR(10) )
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#endif
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FUNCTION FT_GCD(nNumber1, nNumber2)
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LOCAL nHold1, ; // Temporarily Hold the Maximum Number
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nHold2, ; // Temporarily Hold the Minimum Number
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nResult // GCD
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// Either Number Zero??
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IF (nNumber1 == 0 .OR. nNumber2 == 0)
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nResult := 0 // Yes, Can't Have a GCD
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ELSE // No, Calculate the GCD
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nHold1 := MAX(ABS(nNumber1), ABS(nNumber2))
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nHold2 := MIN(ABS(nNumber1), ABS(nNumber2))
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REPEAT
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nResult := nHold1 % nHold2 // Get the Remainder
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nHold1 := nHold2 // Which Makes a New Maximum Number
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nHold2 := nResult // and it's the Minimum Number
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UNTIL nResult <= 0
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nResult := nHold1 // Maximum Number Should Be the Answer
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ENDIF // nNumber1 == 0 or nNumber2 == 0
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RETURN (nResult) // FT_GCD
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