用C++实现日期类，其中包含 日期加上天数结果为一个新日期，日期减去一个天数结果为新日期，两个日期相减结果为相差的天数等等函数的实现。
#pragma once #include #include using namespace std; class Date { private: int _year; int _month; int _day; public: Date(int year=1900, int month=1, int day=1) :_year(year), _month(month), _day(day) { assert(IsInvalid()); } void Display() { cout << _year << "-" << _month << "-" << _day << endl; } bool IsInvalid() { if (_year >= 1900 && _month > 0 && _month<13 && _day>0 && _day <= GetMonthDays(_year, _month)) { return true; } return false; } int GetMonthDays(int year, int month) //计算每个月的天数 { int monthDays[13] = { 0, 31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31 }; if (month != 2) { return monthDays[month]; } else { if ((year % 4 == 0 && year % 100 != 0) || (year % 400 == 0)) { return 29; } else { return 28; } } } Date operator+(int day) //计算一个日期加上天数结果为一个日期 { if (day < 0) { return *this - (-day); } Date tmp(*this); tmp._day += day; while (tmp.IsInvalid() == false) { tmp._day -= GetMonthDays(tmp._year, tmp._month); if (tmp._month == 12) { tmp._year++; tmp._month = 1; } else { tmp._month++; } } return tmp; } Date operator-(int day) //计算日期减去一个天数结果为一个日期 { if (day < 0) { return *this + (-day); } Date tmp(*this); tmp._day -= day; while (tmp.IsInvalid() == false) { if (tmp._month == 1) { tmp._year--; tmp._month = 12; } else { tmp._month--; } int day = GetMonthDays(tmp._year, tmp._month); tmp._day += day; } return tmp; } inline Date& operator+=(int day) { *this = *this + 100; return *this; } inline Date& operator-=(int day) { *this = *this - 100; return *this; } inline Date& operator++() //前加加 { *this += 1; return *this; } inline Date operator++(int) //后加加 { Date tmp(*this); *this += 1; return tmp; } inline Date& operator--() //前减减 { *this -= 1; return *this; } inline Date operator--(int) //后减减 { Date tmp(*this); *this -= 1; return tmp; } bool operator >(const Date& d) //比较大小 { if (_year > d._year || (_year == d._year && (_month > d._month || (_month == d._month&&_day > d._day)))) { return true; } return false; } bool operator>=(const Date& d) { return *this > d || *this == d; } bool operator<(const Date& d) { return!(*this >= d); } bool operator<=(const Date& d) { return (*this > d); } bool operator==(const Date& d) { return _year == d._year &&_month == d._month &&_day == d._day; } bool operator!=(const Date& d) { return !(*this == d); } int operator-(const Date& d) //计算两个日期之差为天数 { int sum1 = 0; int sum2 = 0; int sum3 = 0; int sum = 0; int month = 0; int year = 0; for (month = 1; month < _month; month++) { sum1 += GetMonthDays(_year, month); } sum1 += _day; for (month = 1; month < d._month; month++) { sum2 += GetMonthDays(d._year, month); } sum2 += d._day; sum3 = abs(sum1 - sum2); if (_year == d._year) { return sum3; } else if (_year > d._year) { for (year = d._year; year < _year; year++) { if (((year % 4 == 0) && (year % 100 != 0)) || (year % 400 == 0)) { sum += 366; } else { sum += 365; } } return abs(sum - sum3); } else if (_year < d._year) { for (year = _year; year < d._year; year++) { if (((year % 4 == 0) && (year % 100 != 0)) || (year % 400 == 0)) { sum3 += 366; } else { sum3 += 365; } } return abs(sum - sum3); } } }; void TestDate() { Date d1(2017,3,9); d1.Display(); Date d2(2008,4,20); d2.Display(); int d3 = d1 - d2; cout <<"两个日期相差的天数为：" < << endl; /*Date d2 = d1 +100; d2.Display(); Date d3 = d2 - 100; d3.Display();*/ } test.c #include "Date.h" int main() { TestDate(); return 0; }