Entry

BBCBASIC: Windows: Array: Maximum: How to determine the maximum value of an array?

Feb 2nd, 2006 17:30
Knud van Eeden,

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--- Knud van Eeden --- 02 February 2021 - 11:04 pm -------------------
BBCBASIC: Windows: Array: Maximum: How to determine the maximum value 
of an array?
===
Method: Set the maximum at first to a smallest value possible
---
Steps: Overview:
 1. -Let a variable contain the maximum
 2. -Set this variable equal to some minimum value
     (e.g. the minimum value possible for this variable
           type (e.g. integer))
 3. -Search linearly through the array
     (and so check against all values in the array)
     1. -For first to last value in the array
         1. -Read the value
         2. -If this value is greater than the current maximum
             set the maximum equal to this value
     2. -Endfor
 4. The resulting value will be the maximum
===
Steps: Worked out:
 1. -Create the following program
--- cut here: begin --------------------------------------------------
 maxR = 0
 minI% = 1
 maxI% = 5
 I% = 0
 :
 DIM xR( maxI% )
 :
 FOR I% = minI% TO maxI%
   READ xR( I% )
 NEXT I%
 :
 REM determine the maximum
 maxR = -1E9 : REM initialize maximum to a smallest minimum value
 :
 FOR I% = minI% TO maxI%
   IF ( xR( I% ) > maxR ) THEN maxR = xR( I% )
 NEXT I%
 :
 PRINT "maximum = "; maxR
 :
 END
 :
 :
 :
 DATA 43
 DATA 2
 DATA 789
 DATA 9999
 DATA 6
 :
--- cut here: end ----------------------------------------------------
 2. -If you run this program it will show
      maximum = 9999
===
Method: Set the maximum at first equal to the first element in the 
array
This method has as an advantage that it is directly dependent
on the dataset.
===
Steps: Worked out:
 1. -Create the following program
--- cut here: begin --------------------------------------------------
 maxR = 0
 minI% = 1
 maxI% = 5
 I% = 0
 :
 DIM xR( maxI% )
 :
 FOR I% = minI% TO maxI%
   READ xR( I% )
 NEXT I%
 :
 REM determine the maximum
 maxR = xR( minI% ) : REM set maximum at first equal to first element
 :
 FOR I% = minI% TO maxI%
   IF ( xR( I% ) > maxR ) THEN maxR = xR( I% )
 NEXT I%
 :
 PRINT "maximum = "; maxR
 :
 END
 :
 :
 :
 DATA 43
 DATA 2
 DATA 789
 DATA 9999
 DATA 6
 :
--- cut here: end ----------------------------------------------------
 2. -If you run this program it will show
      maximum = 9999
===
In the following example you pass your array to a function
(using string concatenation)
--- cut here: begin --------------------------------------------------
 minI% = 1
 maxI% = 5
 I% = 0
 :
 DIM xR( maxI% )
 :
 FOR I% = minI% TO maxI%
   READ xR( I% )
 NEXT I%
 :
 PRINT "maximum = "; FNArrayGetMaximumR( minI%, maxI%, "xR(", ")" )
 :
 END
 :
 :
 :
 REM library: determine the maximum
 DEF FNArrayGetMaximumR( minI%, maxI%, arrayBegin$, arrayEnd$ )
 LOCAL maxR
 LOCAL xR
 maxR = EVAL( arrayBegin$ + STR$( minI% ) + arrayEnd$ ) : REM set 
maximum at first equal to first element
 :
 FOR I% = minI% TO maxI%
   xR = EVAL( arrayBegin$ + STR$( I% ) + arrayEnd$ )
   IF xR > maxR THEN maxR = xR
 NEXT I%
 = maxR
 :
 DATA 43
 DATA 2
 DATA 789
 DATA 9999
 DATA 6
 :
--- cut here: end ----------------------------------------------------
 2. -If you run this program it will show
      maximum = 9999
===
In the following example you pass your array to a function
(using direct passing)
--- cut here: begin --------------------------------------------------
 minI% = 1
 maxI% = 5
 I% = 0
 :
 DIM xR( maxI% )
 :
 FOR I% = minI% TO maxI%
   READ xR( I% )
 NEXT I%
 :
 PRINT "maximum = "; FNArrayGetMaximumR( minI%, maxI%, "xR(", ")" )
 :
 END
 :
 :
 :
 REM library: determine the maximum
 DEF FNArrayGetMaximumR( minI%, maxI%, arrayBegin$, arrayEnd$ )
 LOCAL maxR
 LOCAL xR
 maxR = EVAL( arrayBegin$ + STR$( minI% ) + arrayEnd$ ) : REM set 
maximum at first equal to first element
 :
 FOR I% = minI% TO maxI%
   xR = EVAL( arrayBegin$ + STR$( I% ) + arrayEnd$ )
   IF xR > maxR THEN maxR = xR
 NEXT I%
 = maxR
 :
 DATA 43
 DATA 2
 DATA 789
 DATA 9999
 DATA 6
 :
--- cut here: end ----------------------------------------------------
 2. -If you run this program it will show
      maximum = 9999
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Internet: see also:
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BBCBASIC: Windows: Array: Function: How to pass an array to a function?
http://www.faqts.com/knowledge_base/view.phtml/aid/39453/fid/768
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