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copied!<p>Ok, someone pointed out <a href="https://stackoverflow.com/questions/8839943/why-is-it-a-memory-leak-what-could-i-catch-if-i-shall-use-such-things-in-c/8840302#8840302">the memory leak issue</a> to you already.</p> <p>So, you have allocated an array of two animals (<code>ptr = new animal [2];</code>), and stored a pointer to the first one in <code>ptr</code>.</p> <pre><code>+----------+----------+ | speed: 0 | speed: 0 | +----------+----------+ ^ | | ptr </code></pre> <p><sub>(I'm ignoring the <code>position_x</code> and <code>position_y</code>, for the sake of space)</sub></p> <p>Then you set the speed of the first one to 9 (<code>ptr[0].setspeed(9);</code>):</p> <pre><code>+----------+----------+ | speed: 9 | speed: 0 | +----------+----------+ ^ | | ptr </code></pre> <p>Then you do something very weird.</p> <pre><code>ptr++->setspeed(13); </code></pre> <p>Why you do this, I don't know. Don't do this. I'm not joking. I can figure out what this code means, but I would never write something like this. It only serves to sow confusion.</p> <p>But let's pretend it is a sane thing to do for a while... <code>ptr++</code> increments the pointer, and returns the old value.</p> <pre><code>+----------+----------+ | speed: 9 | speed: 0 | +----------+----------+ ^ ^ | | | | result ptr of ptr++ </code></pre> <p>... and then it sets the speed of the animal pointed by that result to 13.</p> <pre><code>+-----------+----------+ | speed: 13 | speed: 0 | +-----------+----------+ ^ ^ | | | | result ptr of ptr++ </code></pre> <p>Finally, <code>ptr->print()</code> prints the the animal pointed by <code>ptr</code>, which is the second one.</p>

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