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1 new exercise: binary-search (#136)
* adding binary-search * fixed binary-search.cut
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‎config.json

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"prerequisites": [],
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"difficulty": 3
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},
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{
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"slug": "binary-search",
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"name": "Binary Search",
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"uuid": "4a580b6d-a370-4526-a5ea-d7c856279676",
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"practices": [],
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"prerequisites": [],
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"difficulty": 3
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},
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{
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"slug": "pascals-triangle",
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"name": "Pascal's Triangle",

‎exercises/practice/binary-search/.docs/instructions.md

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# Instructions
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Implement a binary search algorithm. Do not use any COBOL proprietary
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search routines (eg. SEARCH).
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Searching a sorted collection is a common task. A dictionary is a sorted
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list of word definitions. Given a word, one can find its definition. A
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telephone book is a sorted list of people's names, addresses, and
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telephone numbers. Knowing someone's name allows one to quickly find
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their telephone number and address.
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If the list to be searched contains more than a few items (a dozen, say)
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a binary search will require far fewer comparisons than a linear search,
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but it imposes the requirement that the list be sorted.
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In computer science, a binary search or half-interval search algorithm
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finds the position of a specified input value (the search "key") within
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an array sorted by key value.
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In each step, the algorithm compares the search key value with the key
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value of the middle element of the array.
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If the keys match, then a matching element has been found and its index,
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or position, is returned.
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Otherwise, if the search key is less than the middle element's key, then
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the algorithm repeats its action on the sub-array to the left of the
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middle element or, if the search key is greater, on the sub-array to the
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right.
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If the remaining array to be searched is empty, then the key cannot be
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found in the array and a special "not found" indication is returned.
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A binary search halves the number of items to check with each iteration,
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so locating an item (or determining its absence) takes logarithmic time.
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A binary search is a dichotomic divide and conquer search algorithm.

‎exercises/practice/binary-search/.docs/introduction.md

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# Introduction
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Implement a binary search algorithm.
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Searching a sorted collection is a common task. A dictionary is a sorted
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list of word definitions. Given a word, one can find its definition. A
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telephone book is a sorted list of people's names, addresses, and
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telephone numbers. Knowing someone's name allows one to quickly find
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their telephone number and address.
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If the list to be searched contains more than a few items (a dozen, say)
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a binary search will require far fewer comparisons than a linear search,
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but it imposes the requirement that the list be sorted.
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In computer science, a binary search or half-interval search algorithm
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finds the position of a specified input value (the search "key") within
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an array sorted by key value.
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In each step, the algorithm compares the search key value with the key
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value of the middle element of the array.
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If the keys match, then a matching element has been found and its index,
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or position, is returned.
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Otherwise, if the search key is less than the middle element's key, then
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the algorithm repeats its action on the sub-array to the left of the
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middle element or, if the search key is greater, on the sub-array to the
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right.
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If the remaining array to be searched is empty, then the key cannot be
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found in the array and a special "not found" indication is returned.
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A binary search halves the number of items to check with each iteration,
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so locating an item (or determining its absence) takes logarithmic time.
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A binary search is a dichotomic divide and conquer search algorithm.

‎exercises/practice/binary-search/.meta/config.json

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{
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"authors": [
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"kapitaali"
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],
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"files": {
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"solution": [
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"src/binary-search.cob"
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],
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"test": [
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"tst/binary-search/binary-search.cut"
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],
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"example": [
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".meta/proof.ci.cob"
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],
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"invalidator": [
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"test.sh",
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"test.ps1"
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]
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},
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"blurb": "Implement a binary search algorithm.",
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"source": "Wikipedia",
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"source_url": "http://en.wikipedia.org/wiki/Binary_search_algorithm"
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}

‎exercises/practice/binary-search/.meta/proof.ci.cob

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IDENTIFICATION DIVISION.
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PROGRAM-ID. BINARY-SEARCH.
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AUTHOR. kapitaali.
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ENVIRONMENT DIVISION.
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DATA DIVISION.
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WORKING-STORAGE SECTION.
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01 WS-ITEM PIC 9999.
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01 WS-RESULT PIC 9999.
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01 WS-ERROR PIC X(40) VALUE SPACES.
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01 WS-ARRAY PIC X(60).
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01 L PIC 99 VALUE 0.
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01 R PIC 99.
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01 M PIC 99.
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01 STR PIC X(60).
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01 EXP PIC 999 VALUE ZEROES.
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01 IDX PIC 999.
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01 NUM2 PIC ZZ9 VALUE ZEROES.
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01 COUNTER PIC 999.
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01 LEN PIC 999.
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01 Teibel.
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02 Taulukko PIC 999 OCCURS 1 TO 20
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DEPENDING ON IDX.
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PROCEDURE DIVISION.
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STR-LENGTH.
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MOVE 0 TO LEN.
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PERFORM VARYING COUNTER FROM FUNCTION LENGTH(STR)
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BY -1 UNTIL STR(COUNTER:1) <> " "
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ADD 1 TO LEN
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END-PERFORM.
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COMPUTE LEN = FUNCTION LENGTH(STR) - LEN.
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REVERSE-TABLE.
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COMPUTE R = FUNCTION INTEGER-PART(IDX / 2).
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PERFORM VARYING COUNTER FROM 1 BY 1 UNTIL COUNTER = R
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COMPUTE L = IDX - COUNTER
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MOVE Taulukko(L) TO NUM2
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MOVE Taulukko(COUNTER) TO Taulukko(L)
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MOVE NUM2 TO Taulukko(COUNTER)
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END-PERFORM.
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* populates the table from input string
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MOVE-TO-TABLE.
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MOVE WS-ARRAY TO STR.
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PERFORM STR-LENGTH.
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MOVE 20 TO IDX.
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INITIALIZE Teibel.
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MOVE 3 TO EXP.
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MOVE 1 TO IDX
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MOVE ZEROES TO NUM2.
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PERFORM VARYING COUNTER FROM LEN BY -1 UNTIL COUNTER = 0
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IF WS-ARRAY(COUNTER:1) = ','
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MOVE 3 TO EXP
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MOVE NUM2 TO Taulukko(IDX)
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MOVE ZEROES TO NUM2
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ADD 1 TO IDX
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ELSE IF COUNTER = 1
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MOVE WS-ARRAY(COUNTER:1) TO NUM2(EXP:1)
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MOVE NUM2 TO Taulukko(IDX)
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ADD 1 TO IDX
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ELSE
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MOVE WS-ARRAY(COUNTER:1) TO NUM2(EXP:1)
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SUBTRACT 1 FROM EXP
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END-IF
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END-PERFORM.
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* the actual algorithm
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BINARY-SEARCH.
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MOVE ZERO TO WS-RESULT.
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MOVE SPACES TO WS-ERROR.
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PERFORM MOVE-TO-TABLE.
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IF IDX > 2
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PERFORM REVERSE-TABLE
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END-IF.
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IF L IS LESS THAN 1 OR R IS GREATER THAN IDX
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MOVE "value not in array" TO WS-ERROR
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EXIT PROGRAM
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END-IF.
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MOVE 1 TO L.
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COMPUTE R = IDX - 1.
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PERFORM UNTIL L IS GREATER THAN R
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COMPUTE M = L + R
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COMPUTE M = FUNCTION INTEGER-PART(M / 2)
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IF Taulukko(M) = WS-ITEM
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MOVE M TO WS-RESULT
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EXIT PARAGRAPH
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END-IF
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IF Taulukko(M) IS LESS THAN WS-ITEM
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COMPUTE L = M + 1
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ELSE IF Taulukko(M) IS GREATER THAN WS-ITEM
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COMPUTE R = M - 1
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ELSE
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COMPUTE WS-RESULT = M - 1
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IF Taulukko(WS-RESULT) = WS-ITEM
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EXIT PROGRAM
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ELSE
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MOVE "value not in array" TO WS-ERROR
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EXIT PROGRAM
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END-IF
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END-IF
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END-PERFORM.
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MOVE "value not in array" TO WS-ERROR.

‎exercises/practice/binary-search/bin/fetch-cobolcheck

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#!/usr/bin/env bash
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# This file is a copy of the
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# https://github.com/exercism/configlet/blob/main/scripts/fetch-configlet file.
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# Please submit bugfixes/improvements to the above file to ensure that all tracks benefit from the changes.
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# set -eo pipefail
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readonly LATEST='https://api.github.com/repos/0xE282B0/cobol-check/releases/latest'
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case "$(uname)" in
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Darwin*) os='mac' ;;
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Linux*) os='linux' ;;
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Windows*) os='windows' ;;
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MINGW*) os='windows' ;;
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MSYS_NT-*) os='windows' ;;
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*) os='linux' ;;
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esac
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case "${os}" in
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windows*) ext='.exe' ;;
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*) ext='' ;;
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esac
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arch="$(uname -m)"
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curlopts=(
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--silent
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--show-error
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--fail
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--location
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--retry 3
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)
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if [[ -n "${GITHUB_TOKEN}" ]]; then
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curlopts+=(--header "authorization: Bearer ${GITHUB_TOKEN}")
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fi
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suffix="${os}-${arch}${ext}"
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get_download_url() {
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curl "${curlopts[@]}" --header 'Accept: application/vnd.github.v3+json' "${LATEST}" |
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grep "\"browser_download_url\": \".*/download/.*/cobol-check.*${suffix}\"$" |
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cut -d'"' -f4
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}
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main() {
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if [[ -d ./bin ]]; then
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output_dir="./bin"
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elif [[ $PWD == */bin ]]; then
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output_dir="$PWD"
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else
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echo "Error: no ./bin directory found. This script should be ran from a repo root." >&2
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return 1
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fi
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output_path="${output_dir}/cobolcheck${ext}"
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download_url="$(get_download_url)"
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curl "${curlopts[@]}" --output "${output_path}" "${download_url}"
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chmod +x "${output_path}"
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}
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main

‎exercises/practice/binary-search/bin/fetch-cobolcheck.ps1

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# This file is a copy of the
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# https://github.com/exercism/configlet/blob/main/scripts/fetch-configlet.ps1 file.
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# Please submit bugfixes/improvements to the above file to ensure that all tracks
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# benefit from the changes.
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$ErrorActionPreference = "Stop"
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$ProgressPreference = "SilentlyContinue"
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$requestOpts = @{
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Headers = If ($env:GITHUB_TOKEN) { @{ Authorization = "Bearer ${env:GITHUB_TOKEN}" } } Else { @{ } }
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MaximumRetryCount = 3
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RetryIntervalSec = 1
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}
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$arch = If ([Environment]::Is64BitOperatingSystem) { "amd64" } Else { "x86" }
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$fileName = "cobol-check-windows-$arch.exe"
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Function Get-DownloadUrl {
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$latestUrl = "https://api.github.com/repos/0xE282B0/cobol-check/releases/latest"
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Invoke-RestMethod -Uri $latestUrl -PreserveAuthorizationOnRedirect @requestOpts
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| Select-Object -ExpandProperty assets
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| Where-Object { $_.browser_download_url -match $FileName }
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| Select-Object -ExpandProperty browser_download_url
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}
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$downloadUrl = Get-DownloadUrl
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$outputFile = Join-Path -Path $PSScriptRoot -ChildPath "cobolcheck.exe"
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Invoke-WebRequest -Uri $downloadUrl -OutFile $outputFile @requestOpts

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