date.cpp

#include "Date.h"

Date::Date(unsigned short day = 1 , unsigned short month = 1, int year = 2000): _day(day), _month(month), _year(year){
    if(!isValid()) throw "Date isn`t valid";
}

Date::~Date(void){
}

bool Date::isValid()
{
    if(_month < 1 || _month > 12) return false;
    if(_day < 1 || _day > monthDays(_month, _year)) return false;
    return true;
}

bool Date::isLeapYear(int year)const{
    if ((year % 400 == 0) || ( (year % 4 == 0) && (year % 100 != 0) ))
        return true;
    return false;
}

int Date::operator- (const Date& other){
    int counter = 0;
    int year = other._year;
    int z = 1;
    if(_year < other._year) z = -1;

    while(year!=_year){
        if(isLeapYear(year+= z)) counter+=366;
        else counter+=365;
    }
    counter += dayOfYear()*z;
    counter -= other.dayOfYear()*z;
    return counter*z;
}

bool Date::operator< (const Date& other){
    if(_year * 10000 + _month * 100 + _day < other._year * 10000 + other._month * 100 + other._day) return true;
    return false;
}

bool Date::operator> (const Date& other){
    if(_year * 10000 + _month * 100 + _day > other._year * 10000 + other._month * 100 + other._day) return true;
    return false;
}

int Date::monthDays(int month, int year)const{
    if( month == 1 || month == 3 || month == 5 || month == 7 || 
        month == 8 || month == 10 || month == 12)
        return 31;
    if(month == 4 || month == 6 || month == 9 || month == 11)
        return 30;
    if(isLeapYear(year)) 
        return 29;
    return 28;

}

int Date::dayOfYear()const{
    int day = 0;
    for(int i = 1; i < _month; i++){
        day += monthDays(i, _year);       
    }
    return _day + day;
}