title: How to convert large number strings into integer in c++?
body: <p>Suppose, I have a long string number input in <code>c++</code>. and we have to do numeric operations on it. We need to convert this into the <code>integer</code> or any possible way to do operations, what are those?</p>
  
  <pre><code>string s="12131313123123213213123213213211312321321321312321213123213213";
  </code></pre>