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  1. PO
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    <p>In your case, there is nothing wrong with <code>w</code> and <code>h</code> being a const. You can write your constructor in the following way:</p> <pre><code> MyImage(unsigned int** _image,unsigned int _w,unsigned int _h) : w(_w), h(_h) { // No data is allocated in the memory pointed to by image yet // We have to allocate it here. Remember, that copy-ctor is // a constructor, so it operates on newly created instance, // not on an existing one. image = new unsigned int * [h]; for (int i = 0; i &lt; h; i++) { image[i] = new unsigned int [w]; memcpy(image[i], _image[h], w * sizeof(unsigned int)); } } </code></pre> <p>From my image-processing experience, consider storing an image as a single table, row-by-row. You can access (x, y)-th element by calling <code>data[y * w + x];</code> In such case, you can simplify your copy ctor:</p> <pre><code>MyImage::MyImage(unsigned int * source, int newW, int newH) : w(newW), h(newH) { image = new unsigned int[w * h]; memcpy((void *)image, (void *)source, w * h * sizeof(unsigned int)); } </code></pre> <p>The <em>copy constructor</em>, as C++ community understands this term, would look like this:</p> <pre><code>MyImage::MyImage(const MyImage &amp;source) : w(source.w), h(source.h) { image = new unsigned int[w * h]; memcpy((void *)image, (void *)source.image, w * h * sizeof(unsigned int)); } </code></pre> <p>Notice, that the <code>image</code> field does not exist when you call the constructor, so you do not need to free anything.</p> <pre><code> // Your code MyImage(unsigned int** _image,unsigned int _w,unsigned int _h) { // Class is allocated into some part of memory, which might // have been used, so in effect this may be actually true, // because image may contain some rubbish data if (image) { // But this will result mostly likely in Access Violation // error, because you would try to use (free!) some random // data in memory. for (int i = 0;i &lt; w;++i) delete[] image[i]; delete[] image; } // .. copy _image to imge } </code></pre> <p>If you need an assign-like method, which copies contents of some image (either stored in a unsigned int * or in another Image class) to an <em>existing</em> instance of Image, <code>w</code> and <code>h</code> cannot be const.</p>
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    1. POimage pointer to pointer initialization in C++
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      1. PTQuestion
    1. PTAnswer
    1. USSpook
    1. USSpook
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    1. COI don't think it's any sort of solution.
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      1. PO
      1. USjohn
    2. COWhat is `data`? Anyway, whatever it is, in the constructor it is not initialised, so you will run into undefined behaviour when you try to delete it.
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      1. PO
      1. USGorpik
    3. COYup, haven't noticed, that he wrote a constructor, I guessed indirectly, that he wanted to write an assign-like method which actually would have to remove previous instance of image data.
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