title: Add only even numbers recursively
body: <p>This program is supposed to get a range of values from the user, then it is to add only the even numbers to the range. I have my recursive function running and displaying exactly what it needs to display. I'm just not sure how to do the actual adding of only the even numbers. Could someone help me?</p>
  
  <p>Here is my recursive_function:</p>
  
  <pre><code>int recursive_function(int first_number, int second_number)
  {
  int even_range_sum = 0;
  
  printf("\n    Entering sum function for range %d to %d",
      first_number, second_number);
  if(first_number &lt;= second_number)
  {
      if(is_even(first_number) == 1)
      {
          printf("\n        Adding: %d", first_number);
          recursive_function(first_number + 1, second_number);
      }
      else
      {
          printf("\n        Skipping: %d", first_number);
          recursive_function(first_number + 1, second_number);
      }
  }
  printf("\n    Exiting sum function for range %d to %d ",
      first_number, second_number);
  printf("with result: %d", even_range_sum);
  return even_range_sum;
  }
  </code></pre>
  
  <p>Right now, everything is getting the value zero. Since the variable is redeclared at the beginning of every function and I am not do anything with the variable. Could someone help me know where I am supposed to do the adding. (I can only have one return statement I think) If you need further information just ask. Thanks</p>