title: How do you use Yes/No to input your answer C++?
body: <p>I have my program here.</p>
  
  <pre><code>#include &lt;iostream&gt;
  #include &lt;string&gt;
  using namespace std;
  int main()
  {
  string input;
  cout &lt;&lt; "say yes or no" &lt;&lt; endl;
  cin &gt;&gt; input;
  if(input == Yes)
  {
      cout &lt;&lt; "test" &lt;&lt; endl;
  }
  else if(input == No)
  {
      cout &lt;&lt; "test123" &lt;&lt; endl;
  }
  system("pause");
  }
  </code></pre>
  
  <p>It says that Yes and No are undefined?
  Please help I am new to c++</p>