Editing Program Logic (section)

== 4. primesui — Step-by-Step Logic ==

'''Source:''' <code>primesui.cbl</code><br />
'''Role:''' All output. Manages the <code>primes.prt</code> print file and writes to the system console.

<span id="procedure-division-1"></span>
=== PROCEDURE DIVISION ===

<pre>EVALUATE TRUE on ui-methods
  WHEN start-ui    → PERFORM r90-start-primesui
  WHEN write-ui    → PERFORM r92-write-primesui
  WHEN stop-ui     → PERFORM r99-stop-primesui
  WHEN message-ui  → PERFORM r98-message-ui
  WHEN OTHER       → ui-method-result = 1
EXIT PROGRAM</pre>
<span id="paragraph-r90-start-primesui"></span>
=== 4.1 Paragraph: r90-start-primesui ===

<pre>MOVE 'start-primesui' TO program-paragraph
MOVE 'start-printer'  TO program-message

OPEN OUTPUT fprinter   (primes.prt)

IF primes-prt-status = '00' THEN
  ui-method-result = 0
  SET primes-idx TO 1       ← initialise table column index
  LOG &quot;Open printer Ok&quot;
ELSE
  ui-method-result = 1
  DISPLAY primes-prt-status on console</pre>
<span id="paragraph-r92-write-primesui-called-for-every-prime-row"></span>
=== 4.2 Paragraph: r92-write-primesui ''(called for every prime row)'' ===

<pre>t-ident(primes-idx) = u-sequence   ← load sequence into current cell
t-prime(primes-idx) = u-number     ← load prime value into current cell
SET primes-idx UP BY 1             ← advance to next cell

IF new-page (print-new-page = 1) THEN
  PERFORM r93-new-page             ← write heading + column header

IF primes-idx = 7 THEN             ← 6 entries filled (index is post-increment)
  MOVE primes-table TO print-buffer
  WRITE file-buffer FROM print-buffer   ← write the 132-char data line
  SET primes-idx TO 1

IF linage-counter = 53 THEN        ← within 3 lines of page end
  PERFORM r94-eop</pre>
<span id="paragraph-r93-new-page"></span>
=== 4.3 Paragraph: r93-new-page ===

<pre>MOVE primes-heading TO print-buffer
WRITE file-buffer FROM print-buffer   ← &quot;primes overview&quot;
MOVE table-header  TO print-buffer
WRITE file-buffer FROM print-buffer   ← &quot;Sequence  Prime &quot; × 6
MOVE ZERO TO print-new-page           ← clear new-page flag</pre>
<span id="paragraph-r94-eop-end-of-page"></span>
=== 4.4 Paragraph: r94-eop ''(end-of-page)'' ===

<pre>MOVE page-number    TO f-page-number
MOVE ' '            TO print-buffer
WRITE file-buffer FROM print-buffer   ← blank separator line
MOVE primes-footing TO print-buffer
WRITE file-buffer FROM print-buffer   ← &quot;                    page: NNN&quot;
ADD 1 TO page-number
MOVE 1 TO print-new-page              ← trigger new heading on next write</pre>
<span id="paragraph-r98-message-ui"></span>
=== 4.5 Paragraph: r98-message-ui ===

<pre>DISPLAY process-message UPON scherm   ← writes program-name + paragraph + message to console</pre>
<span id="paragraph-r99-stop-primesui"></span>
=== 4.6 Paragraph: r99-stop-primesui ===

<pre>MOVE 0 TO u-sequence
MOVE 0 TO u-number
PERFORM r92-write-primesui UNTIL new-page   ← pad remaining cells to trigger line flush

MOVE 'stop-primesui' TO program-paragraph
MOVE 'close printer' TO program-message
PERFORM r98-message-ui

CLOSE fprinter

MOVE primes-prt-status TO ui-method-result
IF primes-prt-status = '00' THEN next sentence
ELSE DISPLAY primes-prt-status on console</pre>
<hr/>
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