text: #include <string>
  
  #include "format.h"
  
  using std::string;
  
  // INPUT: Long int measuring seconds
  // OUTPUT: HH:MM:SS
  string Format::ElapsedTime(long seconds)
  { 
      string HH;
      string MM;
      string SS;
      string result;
  
      HH      = std::to_string(int(seconds/3600));
      seconds = int(seconds%3600);
      MM      = std::to_string(int(seconds/60)); 
      seconds = int(seconds%60);
      SS      = std::to_string(int(seconds));;
  
      result  = HH +":" +MM +":"+SS;
      return string(result); 
  }