title: add a lambda and a number
body: <p>I want to accumulate a sum using lambda. so this is my program:</p>
  <pre><code>int maxDistance;
  maxDistance += [&amp;](){
          auto it = itStr1-&gt;begin()+5;
          string pNum{};
          while(*it != ']')
          {
              pNum += *it;
              it++;
          }
          return stoi(pNum);
          };
  </code></pre>
  <p>so naturally, my lambda returns an integer but I got a problem saying :</p>
  <pre><code>Invalid operands to binary expression ('int' and '(lambda at /lsp-17ba31a0-ec96-11eb-be58-cbc5eb4a2b22))
  </code></pre>
  <p>how to solve that ?</p>
  <p>thank you</p>