text: // Exercise 3 from chapter 9
  // This function shows the time elapsed between two provided times.
  
  struct time elapsed_time( struct time t1, struct time t2 )
  {
  
      struct time result;
  
      if( t2.seconds >= t1.seconds )
  	result.seconds = t2.seconds - t1.seconds;
  
      else
  	result.seconds = 60 - t1.seconds + t2.seconds;
  
      if( t2.minutes >= t1.minutes )
  	result.minutes = t2.minutes - t1.minutes;
  
      else
  	result.minutes = 60 - t1.minutes + t2.minutes;
  
      if( t2.hours >= t1.hours )
  	result.hours = t2.hours - t1.hours;
  
      else
  	result.hours = 24 - t1.hours + t2.hours;
  
      return result;
  
  }
  