https://forge.codesys.com/forge/talk/Deutsch/thread/3cf2519113/2020-02-28T11:01:52.072000ZRecent posts to Fehler 3704 Datenrekursion2020-02-28T11:01:52.072000Z2020-02-28T11:01:52.072000ZAnonymoushttps://forge.codesys.com/u/*anonymous/https://forge.codesys.com526ed950e3dfa8ab56fb5a7b41d1c2522dc46921

<div class="markdown_content"><p><em>Originally created by:</em> Bernhard Werner</p> <p>Hallo arno,</p> <p>es ist in der Version 2.3 leider nicht möglich. Da Pointer aber prinzipiell zu allen Pointern und DWORD kompatibel sind, kann man verkettete Listen "hinschummeln":</p> <div class="codehilite"><pre><span></span><span class="nt">TYPE</span> <span class="nt">LinkList</span> <span class="o">:</span> <span class="nt">STRUCT</span> <span class="err"> </span> <span class="err"> </span><span class="nt">i</span> <span class="o">:</span> <span class="nt">INT</span><span class="o">;</span> <span class="err"> </span> <span class="err"> </span><span class="nt">pnext</span> <span class="o">:</span> <span class="nt">DWORD</span><span class="o">;</span> <span class="err"> </span> <span class="err"> </span><span class="nt">pprev</span><span class="o">:</span> <span class="nt">DWORD</span><span class="o">;</span> <span class="nt">END_STRUCT</span> <span class="nt">END_TYPE</span> </pre></div> <p>für Next und Prev dann am besten einfach Funktionen definieren der folgenden Art:</p> <div class="codehilite"><pre><span></span><span class="nv">FUNCTION</span> <span class="nv">NextElem</span> : <span class="nv">POINTER</span> <span class="nv">TO</span> <span class="nv">LinkList</span> <span class="nv">VAR_INPUT</span>    <span class="nv">pelemIn</span> : <span class="nv">POINTER</span> <span class="nv">TO</span> <span class="nv">LinkList</span><span class="c1">;</span> <span class="nv">END_VAR</span> <span class="k">IF</span> <span class="nv">pelemIn</span> <span class="o">=</span> <span class="mi">0</span> <span class="k">THEN</span>    <span class="nv">NextElem</span> :<span class="o">=</span> <span class="mi">0</span><span class="c1">;</span> <span class="k">ELSE</span>    <span class="nv">NextElem</span> :<span class="o">=</span> <span class="nv">pelemIn</span><span class="o">^</span>.<span class="nv">pNext</span><span class="c1">;</span> <span class="nv">END_IF</span> <span class="nv">END_FUNCTION</span> </pre></div> <p>Bernhard Werner</p></div>

2020-02-28T11:01:49.554000Z2020-02-28T11:01:49.554000Zarnohttps://forge.codesys.com/u/arno/https://forge.codesys.com24b690a835a5dd8bb61d4e28d5b8f8c4cf218181

<div class="markdown_content"><p>ist es nicht moeglich, z.B. verkettete listen zu programmieren mit datenstrukturen der form </p> <p>struct elem {</p> <p>i : int ; </p> <p>n : pointer to elem ;</p> <p>p : pointer to elem ; </p> <p>}</p> <p>ich brauche eine zshaengende liste von objecten, aus welcher an beliebiger position eingefuegt und geloescht werden kann.</p> <p>vielen dank vorab </p> <p>arno</p></div>