title: Converting double < - > char
body: <p>I need to create a calculator, for that I have to separte the <code>operands (numbers)</code> and the <code>operators (+Sum, *Mult, -Sub, ^Expo)</code> on different <em>stacks/lists</em> </p>
  
  <p>I need to save each of them on a  stack (wich is a <em>list</em>).<br>
  What I can't do is, how am I supposed to convert the character "+" into double then get it back from double to character ?  Or is there an easier way to do so ? I tried to print this:  </p>
  
  <pre><code>char c = "+";
  double d = c; //Now d = -23.00
  printf("Plus: %c\n", d); //Prints an unknown character "?".  
  </code></pre>
  
  <p>How could I reach where I need ?</p>