title: How to fix error Format specifies type 'char *' but the argument has type 'char'
body: <p>I get a warning saying:
  "Format specifies type 'char *' but the argument has type 'char'" for the student variable.  I am copying/pasting the code out of a book into xcode and am not sure how to fix this.  The only thing that prints in the console is "(lldb)".  Any advice</p>
  
  <pre><code>#include &lt;stdio.h&gt;
  
  void congratulateStudent(char student, char course, int numDays)
  {
      printf("%s has done as much %s Programming as I could fit into %d days.\n", student, course, numDays);
  }
  
  int main(int argc, const char * argv[])
  {
      // insert code here...
      congratulateStudent("mark", "Cocoa", 5);
      return 0;
  }
  </code></pre>