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POUnderstanding OOP Principles in passing around objects/values
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copied!<p>I'm not quite grokking a couple of things in OOP and I'm going to use a fictional understanding of SO to see if I can get help understand.</p> <p>So, on this page we have a question. You can comment on the question. There are also answers. You can comment on the answers.</p> <pre><code>Question - comment - comment - comment Answer -comment Answer -comment -comment -comment Answer -comment -comment </code></pre> <p>So, I'm imagining a very high level understanding of this type of system (in PHP, not .Net as I am not yet familiar with .Net) would be like:</p> <pre><code>$question = new Question; $question->load($this_question_id); // from the URL probably echo $question->getTitle(); </code></pre> <p>To load the answers, I imagine it's something like this ("A"):</p> <pre><code>$answers = new Answers; $answers->loadFromQuestion($question->getID()); // or $answers->loadFromQuestion($this_question_id); while($answer = $answers->getAnswer()) { echo $answer->showFormatted(); } </code></pre> <p>Or, would you do ("B"):</p> <pre><code>$answers->setQuestion($question); // inject the whole obj, so we have access to all the data and public methods in $question $answers->loadFromQuestion(); // the ID would be found via $this->question->getID() instead of from the argument passed in while($answer = $answers->getAnswer()) { echo $answer->showFormatted(); } </code></pre> <p>I guess my problem is, I don't know when or if I should be passing in an entire object, and when I should just be passing in a value. Passing in the entire object gives me a lot of flexibility, but it's more memory and subject to change, I'd guess (like a property or method rename). If "A" style is better, why not just use a function? OOP seems pointless here.</p> <p>Thanks, Hans</p>

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