title: how to pass a variable to command in c
body: <p>I've written a C program on Linux to calculate the perimeter (I've called the perimeter variable "p") of a square from its side length ("l").
  Now I want to use Espeak, a speech synthesis program on Linux to speak the result.
  I've thought of using the "system" method.</p>
  
  <p>For example, if I want to make Espeak speak "hello" inside my program I would do: </p>
  
  <pre><code>system("espeak -v it Hello");
  </code></pre>
  
  <p>Now how can I do with the perimeter?</p>
  
  <pre><code>system ("espeak -v it The perimeter is p"); 
  </code></pre>
  
  <p>doesn't work.</p>