title: Sum integer and char
body: <pre><code>int i = 12;
  char myChar = '4';
  WriteLine(i + myChar);
  </code></pre>
  <p>// 64 because  ASCII '4' = 52</p>
  <pre><code>WriteLine(i  + myChar - '0');
  </code></pre>
  <p>//will be 16, what i want.
  Why i should use  -'0'.</p>