date_class.cpp

#include <iostream>
#include <string>
#include "Date.h"
using namespace std;

const array<unsigned int, 13> Date::days{
        0, 31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31};

Date::Date(int month, int day, int year) {
    setDate(month, day, year);
}

void Date::setDate(int mm, int dd, int yy) {
        if (mm >= 1 && mm <= 12) {
                month = mm;
        }
        else {
                throw invalid_argument{"Month must be 1-12"};
        }
        if ( yy >= 1090 && yy <= 2100) {
                year = yy;
        }
        else {
                throw invalid_argument{"year must be >= 1900 and <= 2100"};
        }

        if ((mm == 2 && leapYear(year) && dd >= 1 && dd <= 29) || (dd >= 1 && dd <= days[mm])) {
                day = dd;
        }
        else {
                throw invalid_argument {
                        "Day is our of range for current month and year"};
        }
}

Date& Date::operator++() {
    helpIncrement();
    return *this;
}

Date Date::operator++(int) {
    Date temp{*this};
    helpIncrement();

    return temp;
}

Date& Date::operator+=(unsigned int additionalDays) {
    for (unsigned int i = 0; i < additionalDays; ++i) {
        helpIncrement();
    }

    return *this;
}

bool Date::leapYear(int testYear) {
        return (testYear % 400 == 0 ||
                (testYear % 100 != 0 && testYear % 4 == 0));
}

bool Date::endOfMonth(int testDay) const {
        if ( month == 2 && leapYear(year)) {
                return testDay == 29;
        }
        else {
                return testDay == days[month];
        }
}

void Date::helpIncrement() {
        if (!endOfMonth(day)) {
                ++day;
        }
        else {
                if (month < 12) {
                        ++month;
                        day = 1;
                }
                else {
                        ++year;
                        month = 1;
                        day = 1;
                }
        }
}

ostream& operator<<(ostream& output, const Date& d) {
        static string monthName[13] = {"", "January", "February", "March", "April", "May", "June", "July",
                "August", "September", "October", "November", "December"};
        output << monthName[d.month] << ' ' << d.day << ", " << d.year;
        return output;
}