//Referencing input and output streams
#include<iostream.h>

int main()
{

//Defining the basic Identifiers
int hours,minutes;
int inthours,intminutes;
int total_time_minutes,total_time_hours;
int total_int_minutes,total_int_hours;
int total_minutes;
char  opSymbol;	

cout <<" Enter the time     (h m):     ";
cin >> hours >>minutes;

cout <<" Enter the interval (h m):     ";
cin >> inthours >>intminutes;


cout <<" Enter the operation (+ or -): ";
cin >> opSymbol;

// Converting hours to minutes e.g. 2 hours* (60 miuntes / hour)
// for both time and interval entries.
total_time_minutes = hours*60 + minutes;
total_int_minutes = inthours*60 + intminutes; 

//Implementing the switch operation here!!
  	switch (opSymbol)
	{
	case '+':	
		total_minutes = total_time_minutes + total_int_minutes;
		break;

	case '-':
		
		total_minutes = total_time_minutes - total_int_minutes;
		if(total_minutes<0)
		{	 
		
			total_minutes=total_minutes+24*60;
		
		}
		
		break;

        default:

		cout<< "Error!  Operation should be + or - only "<<endl;
		break;
	}


cout<< " End time is:                  "<<total_minutes/60<<":"<<total_minutes%60
<<'\n';

return 0;

}

/*
 Enter the time     (h m):     7 15
 Enter the interval (h m):     4 30
 Enter the operation (+ or -): -
 End time is:                  2:45
Press any key to continue
*/