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copied!<p>Using the <code>std::vector<T></code> class:</p> <ul> <li><p>...is <em>just as fast</em> as using built-in arrays, assuming you are doing only the things built-in arrays allow you to do (read and write to existing elements).</p></li> <li><p>...automatically resizes when new elements are inserted.</p></li> <li><p>...allows you to insert new elements <em>at the beginning</em> or <em>in the middle</em> of the vector, automatically "shifting" the rest of the elements "up"( does that make sense?). It allows you to remove elements anywhere in the <code>std::vector</code>, too, automatically shifting the rest of the elements down.</p></li> <li><p>...allows you to perform a range-checked read with the <code>at()</code> method (you can always use the indexers <code>[]</code> if you don't want this check to be performed).</p></li> </ul> <p>There are <strike>two</strike> three main caveats to using <code>std::vector<T></code>:</p> <ol> <li><p>You don't have reliable access to the underlying pointer, which <em>may</em> be an issue if you are dealing with third-party functions that demand the address of an array.</p></li> <li><p>The <code>std::vector<bool></code> class is silly. It's implemented as a condensed bitfield, not as an array. Avoid it if you want an array of <code>bool</code>s!</p></li> <li><p>During usage, <code>std::vector<T></code>s are going to be a bit larger than a C++ array with the same number of elements. This is because they need to keep track of a small amount of other information, such as their current size, and because whenever <code>std::vector<T></code>s resize, they reserve more space then they need. This is to prevent them from having to resize every time a new element is inserted. This behavior can be changed by providing a custom <code>allocator</code>, but I never felt the need to do that!</p></li> </ol> <hr> <p>Edit: After reading Zud's reply to the question, I felt I should add this:</p> <p>The <code>std::array<T></code> class is not the same as a C++ array. <code>std::array<T></code> is a very thin wrapper around C++ arrays, with the primary purpose of hiding the pointer from the user of the class (in C++, arrays are implicitly cast as pointers, often to dismaying effect). The <code>std::array<T></code> class also stores its size (length), which can be very useful.</p>

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