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    <blockquote> <p>how can i return a array in a c++ method and how must i declare it? int[] test(void); ??</p> </blockquote> <p>This sounds like a simple question, but in C++ you have quite a few options. Firstly, you should prefer...</p> <ul> <li><p><a href="http://en.cppreference.com/w/cpp/container/vector" rel="noreferrer"><code>std::vector&lt;&gt;</code></a>, which grows dynamically to however many elements you encounter at runtime, or</p></li> <li><p><a href="http://en.cppreference.com/w/cpp/container/array" rel="noreferrer"><code>std::array&lt;&gt;</code></a> (introduced with C++11), which always stores a number of elements specified at compile time,</p></li> </ul> <p>...as they manage memory for you, ensuring correct behaviour and simplifying things considerably:</p> <pre><code>std::vector&lt;int&gt; fn() { std::vector&lt;int&gt; x; x.push_back(10); return x; } std::array&lt;int, 2&gt; fn2() // C++11 { return {3, 4}; } void caller() { std::vector&lt;int&gt; a = fn(); const std::vector&lt;int&gt;&amp; b = fn(); // extend lifetime but read-only // b valid until scope exit/return std::array&lt;int, 2&gt; c = fn2(); const std::array&lt;int, 2&gt;&amp; d = fn2(); } </code></pre> <p>The practice of creating a <code>const</code> reference to the returned data can sometimes avoid a copy, but normally you can just rely on Return Value Optimisation, or - for <code>vector</code> but not <code>array</code> - move semantics (introduced with C++11).</p> <p>If you really want to use an <em>inbuilt</em> array (as distinct from the Standard library class called <code>array</code> mentioned above), one way is for the caller to reserve space and tell the function to use it:</p> <pre><code>void fn(int x[], int n) { for (int i = 0; i &lt; n; ++i) x[i] = n; } void caller() { // local space on the stack - destroyed when caller() returns int x[10]; fn(x, sizeof x / sizeof x[0]); // or, use the heap, lives until delete[](p) called... int* p = new int[10]; fn(p, 10); } </code></pre> <p>Another option is to wrap the array in a structure, which - unlike raw arrays - are legal to return by value from a function:</p> <pre><code>struct X { int x[10]; }; X fn() { X x; x.x[0] = 10; // ... return x; } void caller() { X x = fn(); } </code></pre> <p>Starting with the above, if you're stuck using C++03 you might want to generalise it into something closer to the C++11 <code>std::array</code>:</p> <pre><code>template &lt;typename T, size_t N&gt; struct array { T&amp; operator[](size_t n) { return x[n]; } const T&amp; operator[](size_t n) const { return x[n]; } size_t size() const { return N; } // iterators, constructors etc.... private: T x[N]; }; </code></pre> <p>Another option is to have the called function allocate memory on the heap:</p> <pre><code>int* fn() { int* p = new int[2]; p[0] = 0; p[1] = 1; return p; } void caller() { int* p = fn(); // use p... delete[] p; } </code></pre> <p>To help simplify the management of heap objects, many C++ programmers use "smart pointers" that ensure deletion when the pointer(s) to the object leave their scopes. With C++11:</p> <pre><code>std::shared_ptr&lt;int&gt; p(new int[2], [](int* p) { delete[] p; } ); std::unique_ptr&lt;int[]&gt; p(new int[3]); </code></pre> <p>If you're stuck on C++03, the best option is to see if the boost library is available on your machine: it provides <code>boost::shared_array</code>.</p> <p>Yet another option is to have some static memory reserved by <code>fn()</code>, though this is NOT THREAD SAFE, and means each call to <code>fn()</code> overwrites the data seen by anyone keeping pointers from previous calls. That said, it can be convenient (and fast) for simple single-threaded code.</p> <pre><code>int* fn(int n) { static int x[2]; // clobbered by each call to fn() x[0] = n; x[1] = n + 1; return x; // every call to fn() returns a pointer to the same static x memory } void caller() { int* p = fn(3); // use p, hoping no other thread calls fn() meanwhile and clobbers the values... // no clean up necessary... } </code></pre>
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    1. POHow to return an array from a function?
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    1. COI don't believe that `new[] int(10)` is a valid new expression. Did you mean `new int[10]` ?
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    2. CO@Charles: probably, I hate being stuck in C# all bloody day then trying to answer something on here... ahhhh... ;-) Totally does my head in.
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