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    copied!<p>You can make a 2D vector. Reference: <a href="http://en.cppreference.com/w/cpp/container/vector" rel="nofollow"><code>std::vector</code></a>:</p> <pre><code>std::vector&lt;std::vector&lt;MyObject&gt;&gt; objects; </code></pre> <p>But before using this object you should have made this object.</p> <pre><code>// you know the size of your 2D : MaxRow, MaxCol std::vector&lt;std::vector&lt;MyObject&gt; &gt; objects(MaxRow, std::vector&lt;MyObject&gt;(MaxCol, MyObject()); </code></pre> <p>Or you can </p> <pre><code>std::vector&lt;std::vector&lt;MyObject&gt; &gt; objects; for(size_t r_i=0; r_i&lt;MaxRow; ++r_i) { // create and push a row in the 2D matrix. objects.push_back(std::vector&lt;MyObject&gt;()); for(size_t c_i=0; c_i&lt;MaxCol; ++c_i) { // push a col in the new created row. objects[r_i].push_back(MyObject()); } } </code></pre> <p>Now you want to access your matrix.</p> <pre><code>size_t row, col; // now you know your row and col : input or from anywhere </code></pre> <p>Lets say that you have a function <code>callObject</code> in <code>MyObject</code> class.</p> <pre><code>// you can do this. objects[row][col].callObject(); </code></pre> <hr> <p>But if you want to store sparse matrices, then you can do</p> <pre><code>std::vector&lt;std::vector&lt;MyObject*&gt;objects(MaxRow, std::vector&lt;MyObject&gt;(MaxCol, nullptr); objects[2][3] = new MyObject(/*your arguments*/); objects[2][3].callObject(); objects[0][0].callObject(); // Boom !!! Null pointer here. </code></pre> <p>With Pointers use, <a href="http://en.cppreference.com/w/cpp/memory/unique_ptr" rel="nofollow">std::unique_ptr</a> or <a href="http://en.cppreference.com/w/cpp/memory/shared_ptr" rel="nofollow">std::shared_ptr</a>.</p> <hr> <p>If you want a Vector2D class you can use it wrap around this vector of vectors.</p> <pre><code> typedef MyObject T; class Vector2D { std::vector&lt;std::vector&lt;T&gt; &gt; objects; public: // initialize the objects with MaxRow rows each with MaxCol cols. Vector2D(size_t MaxRow, size_t MaxCol); // remember that there should already be somebody at this row or col // or you have to create all the rows before this row and all the cols before // this col in this row. void addItem(size_t row, size_t col, const MyObject &amp; obj); }; </code></pre> <p>I used <code>typedef int T</code> because it would be easier for changing to templates.</p> <hr> <p>As i said before, it depends a lot on what you want and your data is. if its kind of sparse, i would have used vector of vector of pointers.</p> <pre><code> typedef MyObject T; class Vector2D { std::vector&lt;std::vector&lt;std::unique_ptr&lt;T&gt; &gt; &gt; objects; public: // initialize the Nullptr with MaxRow rows each with MaxCol cols. Vector2D(size_t MaxRow, size_t MaxCol); // now you can just add the item, as pointer is already there. void addItem(size_t row, size_t col, MyObject * obj); }; </code></pre> <p>Using unique_ptr as it takes care of deletion and other referencing things.</p> <hr> <p>You could have "got a lot of other things" by inheriting <code>std::vector&lt; std::vector&lt;T&gt; &gt;</code> in Vector2D, but composition is better than inheritance in most cases.</p>
 

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