我正在编写一个程序，其中有一部分需要通过重载减号运算符来确定两个日期之间的天数差。
目前，我正盯着屏幕，完全无法思考。我的脑海中有些想法，但它们只是片刻的想法。
在main.cpp中，将有两个变量，例如beethovenDeathDate和beethovenBirthDate，它们将被减去以确定他生活了多长时间。如果我记得正确的话，这大约是22000天。
所以，没有更多的话，这是我的代码：
Date.cpp
const std::string Date::MONTH_STRINGS[] =
{
"", //one based indexing
"January",
"February",
"March",
"April",
"May",
"June",
"July",
"August",
"September",
"October",
"November",
"December"
};
const int Date::DAYS_PER_MONTH[] =
{
0, //one based indexing
31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31
};
Date::Date(int day, int month, int year) : _year(year), _month(month), _day(day)
{
isValid();
}
Date::Date()
{
time_t t = time(0); // get time now
struct tm * now = localtime( & t );
_year = now -> tm_year + 1900;
_month = now -> tm_mon + 1;
_day = now -> tm_mday;
}
int Date::maxDay(int month, int year)
{
int ret = DAYS_PER_MONTH[month];
if(isLeapYear(year) == true && month == 2)
{
++ret;
}
return ret;
}
void Date::addDay(bool forward)
{
if(forward)
{
if(_day < maxDay(_month, _year))
{
++_day;
}
else
{
_day = MIN_DAY;
++_month;
if(_month > MAX_MONTH)
{
_month = MIN_MONTH;
++_year;
}
}
}
else
{
if(_day <= MIN_DAY)
{
--_month;
if(_month < MIN_MONTH)
{
_month = MAX_MONTH;
--_year;
}
_day = maxDay(_month, _year);
}
else
{
--_day;
}
}
}
std::string Date::toString() const
{
if(isValid() == false)
{
return std::string();
}
std::stringstream ss;
ss << MONTH_STRINGS[_month] << " " << _day << ", " << _year;
return ss.str();
}
bool Date::isValid() const
{
if(_month < MIN_MONTH || _month > MAX_MONTH)
{
std::cerr << "Invalid date " << std::endl;
return false;
}
int daysThisMonth = maxDay(_month, _year);
if(_day < MIN_DAY || _day > daysThisMonth)
{
std::cerr << "Invalid date " << std::endl;
return false;
}
return true;
}
bool Date::isLeapYear(int year)
{
if(!(year % 4))
{
if(!(year % 100))
{
if(!(year % 400))
{
return true;
}
else
{
return false;
}
}
else
{
return true;
}
}
else
{
return false;
}
}
bool Date::isLeapYear() const
{
return isLeapYear(_year);
}
bool Date::isLeapDay() const
{
return isLeapDay(_day, _month, _year);
}
bool Date::isLeapDay(int day, int month, int year)
{
if(day == 29 && month == 2 && isLeapYear(year) == true)
{
return true;
}
else
{
return false;
}
}
void Date::addYears(int years)
{
if(years == 0)
{
return;
}
if(isLeapDay() && !isLeapDay(_day, _month, _year + years))
{
_day = Date::DAYS_PER_MONTH[_month];
}
_year += years;
}
void Date::addMonths(int months)
{
if(months == 0)
{
return;
}
int deltayears = months / MAX_MONTH;
int deltamonths = months % MAX_MONTH;
int newMonth = 0;
if(months > 0)
{
newMonth = (_month + deltamonths) % MAX_MONTH;
if((_month + deltamonths) > MAX_MONTH)
{
++deltayears;
}
}
else
{
if((_month + deltamonths) < MIN_MONTH)
{
--deltayears;
newMonth = _month + deltamonths + MAX_MONTH;
}
else
{
newMonth = _month + deltamonths;
}
}
if(_day > maxDay(newMonth, _year + deltayears))
{
_day = maxDay(newMonth, _year + deltayears);
}
_year += deltayears;
_month = newMonth;
}
void Date::addDays(int days)
{
if(days == 0)
{
return;
}
if(days < 0)
{
for(int i = 0; i > days; --i)
{
addDay(false);
}
return;
}
for(int i = 0; i < days; ++i)
{
addDay(true);
}
}
std::ostream& operator<<(std::ostream& os, const Date& date)
{
os << date.toString();
return os;
}
Date Date::operator+(int days) const
{
Date ret = *this;
ret.addDays(days);
return ret;
}
Date& Date::operator+=(int days)
{
addDays(days);
return *this;
}
//This is where I get stumped (the parameters was just one of my failed experiments
Date& Date::operator-(int day, int month, int year)
{
}
days参数。 - smac89