// airtime0.cpp
// class models time data type
// overloads operators

#include "airtime0.h"

airtime airtime::operator + (airtime right)	//overloaded + operator
{	airtime temp;
	temp.hours = hours + right.hours;	// add data
	temp.minutes = minutes + right.minutes;
	if(temp.minutes >= 60)			//check for carry
    	{	temp.hours++;
		temp.minutes -= 60;
    	}
    	return temp;				// return temporary object
}

airtime airtime::operator - (airtime right)	// subtraction operator
{	airtime temp;
	temp.hours = hours - right.hours;
	temp.minutes = minutes - right.minutes;
	if (temp.minutes < 0)
	{	temp.minutes += 60;
       		temp.hours -=1;
    	}
    	return temp;
}

int airtime::operator < (airtime right)		// overloaded < operator
{	if(hours < right.hours)
    		return 1;
	if(hours == right.hours && minutes < right.minutes)
        	return 1;
	return 0;
}

airtime airtime::operator += (airtime right)
{	hours = hours + right.hours;
	minutes = minutes + right.minutes;
	if(minutes >= 60)			// check for carry
	{	hours++;
		minutes -= 60;
	}
	return airtime(hours, minutes);		// return temporary object
}

airtime airtime::operator++ ()			// overloaded prefix ++ operator
{	++minutes;
    	if(minutes >= 60)
    	{	++hours;
        	minutes -= 60;
    	}
    	return airtime(hours, minutes);		// return temporary object
}

airtime airtime::operator++ (int)		// overloaded postfix ++ operator
{	airtime temp(hours, minutes);		// save original value
    	++minutes;				// increment this object
    	if(minutes >= 60)
    	{	++hours;
        	minutes -= 60;
    	}
    	return temp;				// return old original value
}

airtime airtime::operator-()			// negation operator
{						// unary minus
	return airtime(-hours, minutes);
}                                 

istream& operator >> (istream& s, airtime& t) 	// get time
{	char dummy;				// from user
	cout <<"\nEnter time (format 12:59): "; // using
	s >> t.hours >> dummy >> t.minutes;	// overloaded >> operator
	return s;
}

ostream& operator << (ostream& s, airtime t) 
{	s << t.hours << ':' << t.minutes;
	return s;
}