//BetterTime.cpp
//!! marks lines or sections that are new

//!! No #ifndefs etc. here in cpp file

#include<iostream>
  //cout
using namespace std;

#include"BetterTime.h"

//implementation of class functions

bool Time::Set12(int hr, int min, char ap)
//Sets time when given hours and minutes
//in 12 hour format.
//When an invalid time 
//is entered, sets time to noon and 
//returns false.
//noon is 12:00 am, midnight is 12:00 pm.
  {
  //set to a valid time, noon
  hour=12;
  minute=0;
  if ((hr<1) || (min<0) || (min>59) 
             || (hr>12))
        // || is OR
    return 0;  //0 is false

  if ((ap!='a') && (ap!='A') && (ap!='p')
                && (ap!='P'))
        // && is AND
        // symbols in single quotes 
        // are characters
    return 0;
    
  //Got here only if valid time
  if ((ap=='a') || (ap=='A')) // am
        // == is comparison EQUAL
    hour=hr;
        // = is ASSIGNMENT
  else  // pm
    hour=hr+12;
  minute=min;
  if (hour == 24)
    hour = 0;

  return 1; //any nonzero integer is true
  } //end set12

bool Time::Set24(int hr, int min)
//Sets time when given hours and minutes
//in 24 hour format.
//When an invalid time 
//is entered, sets time to noon and 
//returns false.
//noon is 12:00, midnight is 0:00.

  //set default time

  {
  hour = 12;
  minute = 0;
  if ((hr<0) || (min<0) || (min>59) 
             || (hr>=24))
        // || is OR
    return 0;  //0 is false

  hour=hr;
  minute=min;
  return 1; //any nonzero integer is true
  } //end set24


int Time::GetMinutes()
  {return minute;}

int Time::GetHour12()
  {
  if ((hour<=12) && (hour>=1))
    return hour;
  else if (hour==0)
    return 12;
  else
    return hour-12;
  }

int Time::GetHour24()
  {return hour;}

char Time::GetAMPM()
  {
  if (hour>0 && hour<=11)
    return 'A';
  else if ((hour==12) && (minute==0))
    return 'A';
  else if ((hour==0) && (minute>0))
    return 'A';
  else 
    return 'P';
  }  //end GetAMPM

void Time::Display12()
  {
  cout << GetHour12() << ':'
    << minute << ' '
    << GetAMPM() << 'M';
  return;
  }  //end Display12

//!!
//Slightly nicer display
void Time::Display24()
  {
  cout << hour << ':';
  if (minute<10)
    cout << 0;
  cout << minute;
  }

//!! --------------
//All that follows is new

//implementation of operations for the time class
//Notice the answer is the calling object itself, not
//a newly created Time
Time Time::operator++()  
//prefix increment operator
  {
  int min=minute;
  int hr=hour;
  if (++min>59)
    {
    ++hr;
    min=0;
    }
  if (hr==24)
    hr=0;  //next day
  Set24(hr,min);
  return *this;
    //*this is the object that called this function
  } //end operator++

Time Time::operator-(Time right)
    {
    Time result;  //need a place for the answer
    int min, hr;
    min = GetMinutes() - right.GetMinutes();
    hr = GetHour24() - right.GetHour24();
    if (min < 0)
        {
        min=min+60;
        --hr;
        }
    if (hr < 0)
        hr+=24;
    result.Set24(hr, min);
    return result;
    }

bool Time::operator==(Time right)
  {
  return ((GetHour24()==right.GetHour24())
    && (GetMinutes()==right.GetMinutes()));
  }//end operator==

bool Time::operator!=(Time right)
  {
  return !(*this==right);
    //note: uses the function operator==
    //defined above.
  } //end operator!=