title: How to concatenate a std::string and an int
body: <p>I thought this would be really simple, but it's presenting some difficulties. If I have</p>
  <pre><code>std::string name = &quot;John&quot;;
  int age = 21;
  </code></pre>
  <p>How do I combine them to get a single string <code>&quot;John21&quot;</code>?</p>