title: takes null-terminate ascii string, returns int value
body: <p>I'm making two functions.</p>
  
  <p>The functions are main and stringToInt.</p>
  
  <p>In main function has two arguments (int argc, char *argv[]). And it takes arguments from command line. 
  Ex) <code>./a.out 1 2 3 4</code></p>
  
  <p>And second function, I believe to be one argument which is char *argv[].</p>
  
  <p>How would I code that takes null-terminate ASCII string and returns into value in stringToInt function.</p>
  
  <p>Any help/example would be great.</p>
  
  <p>Thanks.</p>