title: push_back a vector into another vector
body: <p>I want to <code>push_back()</code> a vector <code>M</code> into vector <code>N</code>.</p>
  
  <pre><code>#include &lt;iostream&gt;
  #include &lt;vector&gt;
  
  using namespace std;
  
  int main()
  {
      int i = -1;
      vector&lt;vector&lt;int&gt; &gt;N,
      vector&lt;int&gt;M;
      int temp;
  
      while (i++ != 5)
      {
          cin &gt;&gt; temp;
          N.push_back(temp);
      }
  
      N.push_back(vector&lt;int&gt;M);
      return 0;
  }
  </code></pre>
  
  <h2>Compilation error</h2>
  
  <p>I get a syntax error.</p>
  
  <pre><code>test.cpp: In function ‘int main()’:
  test.cpp:28: error: invalid declarator before ‘M’
  test.cpp:34: error: no matching function for call to ‘std::vector&lt;std::vector&lt;int, std::allocator&lt;int&gt; &gt;, std::allocator&lt;std::vector&lt;int, std::allocator&lt;int&gt; &gt; &gt; &gt;::push_back(int&amp;)’
  /usr/include/c++/4.4/bits/stl_vector.h:733: note: candidates are: void std::vector&lt;_Tp, _Alloc&gt;::push_back(const _Tp&amp;) [with _Tp = std::vector&lt;int, std::allocator&lt;int&gt; &gt;, _Alloc = std::allocator&lt;std::vector&lt;int, std::allocator&lt;int&gt; &gt; &gt;]
  test.cpp:37: error: ‘M’ was not declared in this scope
  coat@thlgood:~/Algorithm$ 
  </code></pre>