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POC++ free all memory used by struct
 

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    <p>Quick question; I've googled around and found some answers already, but I'm a bit paranoid so I want to be sure.</p> <p>Consider this situation:</p> <pre><code>struct CoordLocation { float X; float Y; float Z; }; int main() { CoordLocation *coord = new CoordLocation(); delete coord; return 0; } </code></pre> <p>Will calling delete also clear the memory used by the fields X, Y, Z? Some answers I found mentioned that I'd just delete the POINTER, not the actually referenced object this way. What if...</p> <pre><code>struct CoordLocation { float *X; float *Y; float *Z; }; int main() { CoordLocation *coord = new CoordLocation(); delete coord; return 0; } </code></pre> <p>And what if I manually free the memory for each object inside the struct's constructor/destructor?</p> <pre><code>struct CoordLocation { CoordLocation() { *X = new float; *Y = new float; *Z = new float; } ~CoordLocation() { delete X; delete Y; delete Z; } float *X; float *Y; float *Z; }; int main() { CoordLocation *coord = new CoordLocation(); delete coord; return 0; } </code></pre> <p>I noticed that for a simple situation such as:</p> <pre><code> float *a = new float; *a = 5.0f; printf("%f", *a); delete a; printf("%f", &amp;a); </code></pre> <p>printf would print 5.0, so the variable pointed to by a is not exactly destroyed.</p> <p>So my question is: How can I reliably free (as in no memory leaks) ALL the memory used by the struct in this case?</p> <pre><code>struct CoordLocation { float X; float Y; float Z; }; int main() { CoordLocation *coord = new CoordLocation(); delete coord; return 0; } </code></pre> <p>Thanks!</p>
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    1. COYour second `printf` is a bit wrong (format identifier does not match argument type). Did you actually want to write `printf("%f", *a);`, like in the first `printf`?
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      1. USBojan Komazec
    2. COIf you're using a recent/modern compiler, the most reliable way to ensure that **new**'ed memory will be correctly deleted is to use one of the "smart" pointer types available in the C++ standard library. std::unique_ptr and std::shared_ptr take complete ownership of a new'ed object and guarantee that the object they're responsible for won't be leaked. (Ideally you'll never have any _raw_ pointers anywhere in your code)
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      1. USBen Cottrell
    3. COThanks for the tip on the unique_ptr. I'm working with Visual C++ 2008 so the compiler does not support the new standard (can't find unique_ptr in the std namespace). I'll go with the old ways, at least until later on.
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