How to resolve the algorithm Range extraction step by step in the NetRexx programming language

Published on 12 May 2024 09:40 PM

How to resolve the algorithm Range extraction step by step in the NetRexx programming language

Table of Contents

Problem Statement

A format for expressing an ordered list of integers is to use a comma separated list of either Example The list of integers: Is accurately expressed by the range expression: (And vice-versa).

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Step by Step solution about How to resolve the algorithm Range extraction step by step in the NetRexx programming language

Source code in the netrexx programming language

/*NetRexx program to test range extraction. ***************************
* 07.08.2012 Walter Pachl derived from my Rexx Version
* Changes: line continuation in aaa assignment changed
*          1e99 -> 999999999
*          Do -> Loop
*          words(aaa) -> aaa.words()
*          word(aaa,i) -> aaa.word(i)
**********************************************************************/
Say 'NetRexx program derived from Rexx'
aaa='0 1 2 4 6 7 8 11 12 14 15 16 17 18 19 20 21 22 23 24 25 27 28 29'
aaa=aaa' 30 31 32 33 35 36 37 38 39'
say 'old='aaa;
aaa=aaa 999999999                   /* artificial number at the end  */
i=0                                 /* initialize index              */
ol=''                               /* initialize output string      */
comma=''                            /* will become a ',' lateron     */
inrange=0
Loop While i<=aaa.words             /* loop for all numbers          */
  i=i+1                             /* index of next number          */
  n=aaa.word(i)                     /* the now current number        */
  If n=999999999 Then Leave         /* we are at the end             */
  If inrange Then Do                /* range was opened              */
    If aaa.word(i+1)<>n+1 Then Do   /* following word not in range   */
      ol=ol||n                      /* so this number is the end     */
      inrange=0                     /* and the range is over         */
      End                           /* else ignore current number    */
    End
  Else Do                           /* not in a range                */
    ol=ol||comma||n                 /* add number (with comma)       */
    comma=','                       /* to the output string          */
    If aaa.word(i+2)=n+2 Then Do    /* if the nr after the next fits */
      inrange=1                     /* open a range                  */
      ol=ol'-'                      /* append the range connector    */
      End
    End
  End
Say 'new='ol

/* NetRexx */
options replace format comments java crossref symbols nobinary

runSample(arg)
return

-- ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~
-- Compact a list of numbers by reducing ranges
method compact(expanded) public static
  nums = expanded.changestr(',', ' ').space -- remove possible commas & clean up the string
  rezult = ''

  RANGE = 0
  FIRST = nums.word(1) -- set starting value
  loop i_ = 2 to nums.words -- each word in the string is a number to examine
    LOCAL = nums.word(i_)
    if LOCAL - FIRST - RANGE == 1 then do
      -- inside a range
      RANGE = RANGE + 1
      end
    else do
      -- not inside a range
      if RANGE \= 0 then do
        -- we have a range of numbers so collect this and reset
        rezult = rezult || FIRST || delim(RANGE) || FIRST + RANGE || ','
        RANGE = 0
        end
      else do
        -- just collect this number
        rezult = rezult || FIRST || ','
        end
      FIRST = LOCAL -- bump new starting value
      end
    end i_

  if RANGE \= 0 then do
    -- terminating value is a range
    rezult = rezult || FIRST || delim(RANGE) || FIRST + RANGE
    end
  else do
    -- terminating value is a single number
    rezult = rezult || FIRST
    end

  return rezult.space(1, ',') -- format and return result string

-- ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~
-- determine if the range delimiter should be a comma or dash
method delim(range) private static
  if range == 1 then dlm = ','
  else               dlm = '-'
  return dlm

-- ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~
-- sample driver
method runSample(arg) public static 

parse arg userInput
td = 0
if userInput.words > 0 then do
  -- use input from command line
  td[0] = td[0] + 1; r_ = td[0]; td[r_] = userInput
  end
else do
  -- use canned test data
  td[0] = td[0] + 1; r_ = td[0]; td[r_] = ' -6,  -3,  -2,  -1,   0,   1,   3,  4,  5,   7,  8,  9, 10, 11, 14, 15, 17, 18, 19, 20'
  td[0] = td[0] + 1; r_ = td[0]; td[r_] = '  0,   1,   2,   4,   6,   7,   8, 11,  12, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 27, 28, 29, 30, 31, 32, 33, 35, 36, 37, 38, 39'
  td[0] = td[0] + 1; r_ = td[0]; td[r_] = ' -4,  -3,  -2,   0,   1,   2,   4,  6,  7,   8, 11, 12, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 27, 28, 29, 30, 31, 32, 33, 35, 36, 37, 38, 39'
  end

loop r_ = 1 to td[0]
  say 'Original: ' td[r_].changestr(',', ' ').space(1, ',')
  say 'Compacted:' compact(td[r_])
  say
  end r_
return

  

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