/** Time.cpp -- implements the Time member functions **/

#include "Time.h"

/*** Utility Functions -- Prototypes ***/

int ToMilitary(unsigned hours, unsigned minutes, char am_pm);

//----- Function to implement the Set operation -----

void Time::Set(unsigned hours, unsigned minutes, char am_pm)
{ 
  // Check class invariant
  if (hours >= 1 && hours <= 12 && 
      minutes >= 0 && minutes <= 59 && 
      (am_pm == 'A' || am_pm == 'P'))
  {
    myHours = hours;
    myMinutes = minutes;
    myAMorPM = am_pm;
    myMilTime = ToMilitary(hours, minutes, am_pm);
  }
  else
    cout << "*** Can't set time with these values ***\n";
    // Object's data members remain unchanged
}

//----- Function to implement the Display operation -----

void Time::Display(ostream & out) const
{
  out << myHours << ':'
      << (myMinutes < 10 ? "0" : "") << myMinutes 
      << ' ' << myAMorPM << ".M.  ("
      << myMilTime << " mil. time)";
}


/*** Utility Functions -- Definitions ***/

/* ToMilitary converts standard time to military time.
 *
 *  Receive: hours, minutes, am_pm
 *  Return:  The military time equivalent
 ********************************************************/

int ToMilitary (unsigned hours, unsigned minutes, char am_pm)
{
  if (hours == 12)
    hours = 0;

  return hours * 100 + minutes + (am_pm == 'P' ? 1200 : 0);
}