Task 1

Given:
class DateTime{
public:
DateTime(int y, int m, int d, int h = 0, int min = 0, int s = 0);
void display();
protected:
string get_string_component(char option, tm* dateStruct);
int get_year_days(tm* dateStruct);
struct tm DTstruct;
private:
bool validate_data( int y, int m, int d, int h, int min, int s);
};

string DateTime::get_string_component(char component, tm* dateStruct){
char format[3];
format[0] = '%';
format[1] = component;
format[2] = '\0';

char ans [80];
strftime(ans, 80, format, dateStruct);
string strans(ans);
return strans;
}

int DateTime::get_year_days(tm* DTstruct){
return DTstruct->tm_yday;
}

Implement member functions
- DateTime(int y, int m, int d, int h = 0, int min = 0, int s = 0);

Assign proper values to DTStruct members using the (default) arguments.

y should be a four digit integer and DTstruct.tm_year is a two digit integer.
  E.g. user input 1994, DTstruct.tm_year is 94.
  E.g. user input 2015, DTstruct.tm_year is 15.
m is from 1 to 12, but DTstruct.tm_mon is from 0 to 11.
d and DTstruct.tm_mday have the same value.
h and DTstruct.tm_hour have the same value.
min and DTstruct.tm_min have the same value.
s and DTstruct.tm_sec have the same value.
DTstruct.tm_wday, DTstruct.tm_yday and DTstruct.tm_isdst will be set to 0 initially.
Re-adjust values in DTstruct.

- void display();
Display the local date and time of DTstruct.

- bool validate_data( int y, int m, int d, int h, int min, int s);
return true if all parameter values are all valid;
return false when one or more data are invalid;
a false return will invoke the exit(EXIT_FAILURE) function call and display
the following error message:
"Incompatible data!"
Validation criteria:

We can retrieve any one of the date-time structure member using strftime(). Refer to Assignment 1 for options available.

You have to provide:
- a header file datetime.h with code to prevent multiple inclusion.
- an class implementation file datetime.cpp.
- a text file task_2_1.txt containing compilation messages and sample runs.

Task 2

Derive class WeekDay from class DateTime such that WeekDay::display() will display local date time using values from the parameters and the corresponding weekday. For a handy online weekday calculator: What Day is this Date?

class WeekDay : public DateTime {

public:
WeekDay(int y, int m, int d, int h = 0, int min = 0, int s = 0);
void display();
};

Implement

- WeekDay(int y, int m, int d, int h = 0, int min = 0, int s = 0);

Validate the parameter values the same ways as in DateTime().
- void display();
display the local date time and the corresponding weekday.

You have to provide:
- a header file weekday.h with code to prevent multiple inclusion.
- an class implementation file weekday.cpp.
- a text file task_2_2.txt containing compilation messages and sample runs.

Task 3

Derive class Age from class DateTime such that Age::display() will display birthdate in local date time format using values from the parameters, the current time and the age.

class Age : public DateTime {
public:
// Date supplied is birth date, should be earlier than current date
Age(int y, int m, int d, int h = 0, int min = 0, int s = 0);
void display();
protected:
struct tm Astruct; // tm for current time
private:
string int_2_string(int);
void error_action();
string age;
};

string Age::int_2_string(int n){
ostringstream outstr;
if (n > 100000){
outstr << (n - 100000);
return outstr.str() + " days old.";
} else if (n > 1000){
outstr << (n - 1000);
return outstr.str() + " months old.";
} else {
outstr << n;
return outstr.str() + " years old.";
}
}

void Age::error_action(){
cout << "Birthday must be in the past!\n";
exit(EXIT_FAILURE);
}

Implement
- Age(int y, int m, int d, int h = 0, int min = 0, int s = 0);
Validate parameter values the same way as in class DateTime.
When calculating age, the unit can be day, month or year. To differentiate the units,
add 1,000 to age in months, add 100,000 to age in days. When passed to
int_2_string, we can convert the age to proper values and units.
- void display();
Display the local date time created as birthdate; the current date and the age
calculated using the birthdate and the current date.
You have to provide:
- a header file age.h with code to prevent multiple inclusion.
- an class implementation file age.cpp.
- a text file task_2_3.txt containing compilation messages and sample runs.

Task 4
Derive class Days2Go from class DateTime such that Days2GoAge::display() will display birthdate in local date time format using values from the parameters and the number of days before your next birthday. The current date used in the sample run is assumed to be 15/04/2015.

class Days2Go : public Age {
public:
Days2Go(int y, int m, int d, int h = 0, int min = 0, int s = 0);
void display();
private:
int days;
};

Implement
- Days2Go(int y, int m, int d, int h = 0, int min = 0, int s = 0); 2016 is a leap year.
Birth year may be a leap year. You have to consider 29 Feb.
- void display();
Display the local date time created as birthdate; the current date and the age
calculated using the birthdate and the current date.
You have to provide:
- a header file days2go.h with code to prevent multiple inclusion.
- an class implementation file days2go.cpp.
- a text file task_2_4.txt containing compilation messages and sample runs.

Task 5

Write a C++ program that stores information for date-time objects including DateTime, WeekDay, Age, and Days2Go objects. The program will display all the object information using the display() function provided by the objects.

Note
- Use a single vector to store information for all objects. Arrays, and other data structures are not allowed.
- When displaying information, the corresponding display() function of the object should be used.
E.g. DateTime object will display local date time and Age object will display birthdate, current date and age.
- You may have to modify the class interface(s) to enable polymorphism.
- There is no need to implement error exception.
- Adjust current date to 15 Apr 2015.
- You have to submit date.h, date.cpp, task_2_5.cpp and task_2_5.txt containing compilation messages and sample runs.
- Dates to be stored:
DateTime: 1990, Jan, 7, 14:15:16
DateTime: 2000, Mar, 14, 14:15
DateTime: 2015, Apr, 15, 14 hour
DateTime: 2015, Apr, 10
DateTime: 2015, Feb, 16
DateTime: 2000, Feb, 16

WeekDay: 1990, Jan, 7, 14:15:16
WeekDay: 2000, Mar, 14, 14:15
WeekDay: 2015, Apr, 15, 14 hour
WeekDay: 2015, Apr, 10
WeekDay: 2015, Feb, 16
WeekDay: 2000, Feb, 16

Age: 1990, Jan, 7, 14:15:16
Age: 2000, Mar, 14, 14:15
Age: 2015, Apr, 15, 14 hour
Age: 2015, Apr, 10
Age: 2015, Feb, 16
Age: 2000, Feb, 16

Days2Go: 1990, Jan, 7, 14:15:16
Days2Go: 2000, Mar, 14, 14:15
Days2Go: 2015, Apr, 15, 14 hour
Days2Go: 2015, Apr, 10
Days2Go: 2015, Feb, 16
Days2Go: 2000, Feb, 16