First commit

LICENSE.txt

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+MIT License
+
+Copyright (c) [2025] [Wayne Jackson]
+
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to deal
+in the Software without restriction, including without limitation the rights
+to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in all
+copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+SOFTWARE.

README.md

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+# sqrtnewton
+
+This is a COBOL rewrite of a Fortran program that is a rewrite of a REXX script that I came across similar to the one on Wikipedia [Rexx](https://en.wikipedia.org/wiki/Rexx) to find the square root of a positive number.
+
+I have modified the code to include:
+- Correct for negative numbers
+- Set a limit for iterations
+- Set tolerances for 32 bit REAL numbers
+- It also sanitises the input in case the user types something other than a number, also JES/JCL seems to not like numbers all that much being passed by SYSIN
+
+This all came about as I am doing some courses on using the z/OS and writing code in REXX is one of the course modules.
+
+I got bored.

sqrnewt.cbl

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+       IDENTIFICATION DIVISION.
+      * A rewrite of a fortran program that is rewrite of a REXX script
+      * to find the square root of a number
+
+       PROGRAM-ID.    SQRNEWT.
+       AUTHOR.        Wayne.
+
+       DATA DIVISION.
+       WORKING-STORAGE SECTION.
+       01 WORK-AREA.
+           05 MAX-ITER      PIC  9(3)       VALUE  100.
+           05  ITER         PIC  9(3).
+           05  TOL          PIC  9(3)V9(12)  VALUE  0.0000000001.
+           05  RR           PIC S9(3)V9(12).
+           05  R            PIC S9(3)V9(12).
+           05  N            PIC S9(3)V9(12).
+           05  N-TEXT       PIC X(15).
+           05  DIS-RESULTS  PIC Z(3).9(12).
+
+       PROCEDURE DIVISION.
+           DISPLAY "Enter a 3 digit value <> 0:"
+      *    ACCEPT N FROM PARMS
+      *    MOVE 4 TO N
+           ACCEPT N-TEXT
+
+           PERFORM VALID-INPUT
+           STOP RUN.
+
+      *    Validate the input
+      *    If less than 0 ie negative, make it positive
+      *    If 0 then drop out
+       VALID-INPUT.
+           INSPECT N-TEXT REPLACING ALL "," BY "."
+           COMPUTE N = FUNCTION NUMVAL(N-TEXT)
+      *    DISPLAY N
+
+           IF N LESS THAN ZERO THEN
+             COMPUTE N = N * (- 1)
+             DISPLAY "CORRECTED FOR NEGATIVE VALUE"
+           END-IF.
+
+           IF N NOT EQUAL ZERO THEN
+             PERFORM FIND-SQRROOT
+           ELSE
+             DISPLAY "CANNOT BE ZERO"
+           END-IF.
+       END-VALID-INPUT.
+
+      *    Find the SQR Root of a number
+       FIND-SQRROOT.
+           MOVE 0 to ITER
+           MOVE 1 to R
+
+           PERFORM UNTIL ITER GREATER OR EQUAL MAX-ITER
+             COMPUTE ITER = ITER + 1
+             COMPUTE RR = (N / R + R) / 2
+
+             IF (FUNCTION ABS(RR - R) <= TOL) THEN
+               EXIT PERFORM
+             END-IF
+
+             MOVE RR TO R
+           END-PERFORM
+
+           MOVE RR TO DIS-RESULTS
+           DISPLAY DIS-RESULTS.
+       END-FIND-SQRROOT.
+

sqrnewt.jcl

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+//SQRNEWT JOB 1,NOTIFY=&SYSUID
+//***************************************************/
+//COBRUN  EXEC IGYWCL
+//COBOL.SYSIN  DD DSN=&SYSUID..CBL(SQRNEWT),DISP=SHR
+//LKED.SYSLMOD DD DSN=&SYSUID..LOAD(SQRNEWT),DISP=SHR
+//***************************************************/
+// IF (RC = 0) THEN
+//***************************************************/
+//RUN     EXEC PGM=SQRNEWT
+//STEPLIB   DD DSN=&SYSUID..LOAD,DISP=SHR
+//SYSOUT    DD SYSOUT=*
+//SYSIN     DD *
+15
+/*
+//SYSUDUMP  DD DUMMY
+//***************************************************/
+// ENDIF