title: Also convert upper case to lower case to count
body: <p>I have a code that I am supposed to make it go through a list of names and count how many times a letter is used. So far it works for lower case but how do I implement upper case into the picture.
  I greatly appreciate the help.</p>
  
  <pre><code>/*                                                                              
   * Search through each character in s,                                          
   * which is array containing n strings,                                         
   * and update the global count array                                            
   * with the correct character counts.                                           
   * Note: check the examples to see                                              
   * if the counts should be case                                                 
   * sensitive or case insensitive.                                               
   */
  void letterCount(char * s[], int n){
    //Implement this function                                                     
    int c = 0,x,i;
    char p = 'a', j = 'z', A = 'A', Z = 'Z';
    while (c&lt;n) {
      for(i=0;s[c][i]!='\0';i++){
        if (s[c][i] &gt;= p &amp;&amp; s[c][i] &lt;= j ){
          x = s[c][i] - 'a';
          count[x]++;
        }
        c++;
      }
    }
  }
  </code></pre>