date class [version 971]

Bjarne Stroustrup “Programming Principles and Practice Using C++”
Chapter 9 Drill 4
Using std_lib_facilities.h by Bjarne Stroustrup.

[code language=”cpp”]
// Philipp Siedler
// Bjarne Stroustrup’s PPP
// Chapter 9 Drill 4

#include "std_lib_facilities.h"

class Date {
public:
enum Month {
jan = 1, feb, mar, apr, may, jun, jul, aug, sep, oct, nov, dec
};

Date(int y, Month m, int d);
void add_day(int n);

int year() const { return y; }
Month month() const { return m; }
int day() const { return d; }

private:
int y;
Month m;
int d;
};

Date::Date(int y0, Date::Month m0, int d0) {
d = d0;
m = m0;
y = y0;
}

void Date::add_day(int n) {
d += n;
}

static ostream & operator<< (ostream & os, const Date::Month & m) {
switch (m) {
case Date::jan: os << "January"; break;
case Date::feb: os << "February"; break;
case Date::mar: os << "March"; break;
case Date::apr: os << "April"; break;
case Date::may: os << "May"; break;
case Date::jun: os << "June"; break;
case Date::jul: os << "July"; break;
case Date::aug: os << "August"; break;
case Date::sep: os << "September"; break;
case Date::oct: os << "October"; break;
case Date::nov: os << "November"; break;
case Date::dec: os << "December"; break;
}
return os;
}

ostream & operator<< (ostream & os, const Date & dd) {
os << "Year: " << dd.year() << " Month: " << dd.month() << " Day: " << dd.day() << endl;
return os;
}

int main()
try
{
Date today{ 1978, Date::jun, 25 };
Date tomorrow = today;
tomorrow.add_day(1);

cout << today;
cout << tomorrow;

keep_window_open();
}

catch (runtime_error e) {
cout << e.what() << ‘\n’;
keep_window_open();
}
catch (…) {
cout << "Exiting" << ‘\n’;
keep_window_open();
}
[/code]

Output:
Year: 1978 Month: June Day: 25
Year: 1978 Month: June Day: 26
Please enter a character to exit