Date/Time calculator assignment

[Kerskjee]

I have an assignment at school, where we are to "fill inn" the empty gaps in this date/time calculator. I have to fill in the "commands" section and the "class-functions" section, I've tried my hand at it, but I'm in way too deep. I get that its probably hard to figure it out without any more information, but if anybody on here could make it work with the information given, I'd be extremely thankful.

//  INCLUDE:
#include <iostream>          //  cout, cin
#include <cctype>            //  toupper

using namespace std;

//  CLASS:
class DateTime {                  // Class contains data about:
private:
	int day, month, year;     //    - A given date and
	int hour, minute, second;  //    - A given time.

	bool  leapYear(int ye);
	int   dayNumber(int da, int mo, int ye);

public:
	DateTime();                    //  2x constructores:
	DateTime(int hh, int mm, int ss);
	void writeDate();         //  Form:  dd/mm-yyyy
	void writeTime();         //  Form:  hh:mm:ss
	void writeDateTime();     //  Form:  dd/mm-yyyy   hh:mm:ss
	void readDate();          //  Reads new date.
	void readTime();          //  Reads new time.
	void readDateTime();      //  Reads new date and new time.
	bool sameDate(const DateTime t);         // Same date or not.
	DateTime  timeDifference(const DateTime tt);  // Time difference between two "time"s, same date
	int  DateDifference(const DateTime tt);  //  Number of days between two "date"s
};

// Declaration of functions:
void writeMenu();
char readCommand();
int  read(const int min, const int max);



//  ********************  M A I N P R O G R A M :  ************************
int main() {
	DateTime dt1, dt2, dt3;  //  Three DateTime-objects.

	char choice;             //  Users choice/command.
	int nr;                  //  Which of dt1 and dt2 should be changed.

	writeMenu();             //  Writes/prints user-menu.
	choice = readCommand();  //  Reads users choice/command.

	 //        This i Haven't filled in yet

	while (choice != 'Q'  &&  choice != 'A') {  //  as long as, don't quite:
		switch (choice) {
			//  Prints out both "DateTime"s (dt1 and dt2)(= date + time)
		case 'S':    /*  fill in  */  ()   break;

			//  Change date (either dt1 or dt2)
		case 'D':    /*  fill in  */  ()   break;

			//  Change time (either dt1 or dt2)
		case 'P':    /*  fill in  */  ()   break;

			//  Change DateTime (= date + time) (either dt1 or dt2)
		case 'T':    /*  fill in  */  ()   break;

			//  checks if dates in dt1 and dt2 are the same
			//  if not print out a massage saying so. 
			//  But if it is the same date, find the time difference
		case 'X':    /*  fill in  */  ()   break;

			// prints number of days between dt1 and dt2
		case 'Y':    /*  fill in  */  ()   break;

		default:   writeMenu();   break;
		}
		choice = readCommand(); //  Reads again users choice/command.
	}
	cout << "\n\n";
	return 0;
}


//  *******************  DEFINITION OF CLASS-FUNCTIONS:  ********************

bool DateTime::leapYear(int ye) {    //  Checks if leap year:
	if ((ye % 400 == 0) || ((ye % 4 == 0) && (ye % 100) != 0))
		return true;            //  Leap year if: (dividable by 400)
	else                            //  OR (dividable by 4 AND not with 100)
		return false;
}

int DateTime::dayNumber(int da, int mo, int ye) {
	//  Puts up number of days in month.
	//   Value for February is set later.
	int daysPrMonth[12] = { 31, 0, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31 };
	int totalDaynr, i;

	if (ye < 1600 || ye > 2100) return 0;    //  not allowed year.
	if (mo < 1 || mo > 12)   return 0;       //  not allowed month
         //  depending on wether or not the year is a leap year,
	 //  the value of February is set:
	daysPrMonth[1] = (leapYear(ye)) ? 29 : 28;
	if (da < 1 || da > daysPrMonth[mo - 1])  return 0;  // not allowed day:
	//  Guarantied an allowed date  !!
	totalDaynr = da;
	for (i = 0; i < mo - 1; i++)        // Calculated the date's daynumber.
		totalDaynr += daysPrMonth[i];

	return totalDaynr;                          // Returns daynumber.
}


DateTime::DateTime()	            //  2x constructores, that sets valus:
	:day(1), month(1), year(2000), hour(0), minute(0), second(0)
{
}

DateTime::DateTime(int hh, int mm, int ss)
	: day(1), month(1), year(2000), hour(hh), minute(mm), second(ss)
{
}

void DateTime::writeDate()                 //  Form:  dd/mm-yyyy
{
	cout << day << "/" << month << "-" << year << endl;
}

void DateTime::writeTime()                 //  Form:  hh:mm:ss
{
	cout << ((hour < 10) ? "0" : "") << hour
		<< ((minute < 10) ? "0" : "") << minute
		<< ((second < 10) ? "0" : "") << second << endl;
}

void DateTime::writeDateTime()             //  Form:  dd/mm-yyyy   hh:mm:ss
{
	writeDate();
	writeTime();
}

void DateTime::readDate()                 //  reads new date:
{
	writeDate();
	cout << "Input day (1-31)\n";
	day = read(1, 31);
	cout << "Input month (1-12)\n";
	month = read(1, 12);
	cout << "Input year (1600-2100)\n";
	year = read(1600, 2100);
	dayNumber(day, month, year);

}

void DateTime::readTime()                //  Reads new time:
{
	writeTime();
	cout << "Input hour  (0-23)\n";
	hour = read(0, 23);
	cout << "Input minute (0-59)\n";
	minute = read(0, 59);
	cout << "Input second (0-59)\n";
	second = read(0, 59);

}

void DateTime::readDateTime()            //  Reads new date and new time:
{
	readDate();
	readTime();
}

bool DateTime::sameDate(const DateTime t)             //  Same date or not:
{
	return(day == t.day && month == t.month && year == t.year)
}
//  difference between to "time"s
DateTime DateTime::timeDifference(const DateTime tt)
{
	//  Gave up here. 
	//  The thought was: turn it into seconds, then back into the "time" format

	int timeSec, tempH, tempM, tempS;
	timeSec = ((hour * 60) + minute) * 60;



	tempM = timeSec / 60;
	tempS = timeSec % 60;
	tempH = tempM / 60;
	tempM = tempM % 60;



	return DateTime(tempH, tempM, tempS)
}
//  Number of days between "date"s
int DateTime::DateDifference(const DateTime tt)
{   //  No idea what do do here
}



//  ***********************  DEFINITION OF FUNCTIONS:  ***********************

void writeMenu() {         //  Prints the user's choices/commands:
	cout << "\n\nFollowing commands are allowed:\n";
	cout << "\tS   - Prints both \"DateTime\"s\n";
	cout << "\tD   - Date-input\n";
	cout << "\tP   - Time-input\n";
	cout << "\tT   - DateTime-input (= Date + Time)\n";
	cout << "\tX   - Time-difference (when same date)\n";
	cout << "\tY   - Date-difference\n";
	cout << "\tQ/A - Quit / Avslutt\n";
}


char readCommand() {       //  Reads user's choice/command:
	char ch;
	cout << "\n\nGive command (S, D, P, T, X, Y, Q/A):  ";  // Asks for char
	cin >> ch;    ch = toupper(ch);        //  Reads and upcaser char.
	return ch;                             //  Returns char/command.
}

//  Reads and returns value in [MIN, MAX]:
int read(const int min, const int max) {
	int numb;                     //  Written number variable.
	cin >> numb;                  //  Reads number.
	while (numb < min || numb > max) {    //  outside allowed interval:
		cout << "\tinside interval (" << min << '-' << max << "):  ";
		cin >> numb;
	}
	return numb;                  //  Returns allowed number
}