【C++】实现万年历

1.此万年历功能

1>日期加减天数

2>日期与日期之间的差值

3>输入年月显示当月日历

2.代码实现

#include<iostream>#include<iomanip>using namespace std;class Date{public:Date(int year = 1990, int month = 1, int day = 1)  //构造函数:_year(year), _month(month), _day(day){if (JudgeRightDate())     //判断传入的值是否是合法的，不合法则置成1990年1月1日{_year = 1990;_month = 1;_day = 1;}}bool JudgeRightDate()   //判断值是否合法函数{if (_year < 1 || ((_month< 1)||_month>12) ||(_day<1)||_day>GetMonthDay(_year,_month)){return true;}else{return false;}}int JudgeYear(int year)   //判断是否是闰年的函数{if (((year % 4 == 0) && (year % 100 != 0)) || (year % 400 == 0)){return 1;}elsereturn 0;}int GetMonthDay(int year, int month)  //通过年和月得到对应的天数{int arr[13] = { 0, 31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31 };int days = arr[month];if (month == 2){days += JudgeYear(year);   //如果是闰年的二月则天数加1}return days;}Date operator +(int days)    //日期加天数函数，重载“+”实现{_day += days;            //先将天数全部加到所给日期的“天”上GetRightDate(_year, _month, _day);  //再通过计算得到正确的日期。return *this;}void GetRightDate(int &year, int &month, int &day)   //计算出正确的日期{if (day <= 0){while (day <= 0){month--;day += GetMonthDay(year, month);if (month < 1){year--;month = 13;}}}else{while (day>GetMonthDay(year, month)){day -= GetMonthDay(year, month);month++;if (month > 12){year++;month = 1;}}}}Date operator -(int days)   //重载“-”实现日期减天数{_day -= days;GetRightDate(_year, _month, _day);return *this;}bool operator >(const Date &d)   //判断两个日期的大小{if (_year > d._year){return true;}else if (_year == d._year){if (_month > d._month){return true;}else if (_month==d._month){if (_day > d._day){return true;}}}return false;}bool operator ==(const Date &d)   //判断两个日期是否相等{if (_year == d._year && _month == d._month && _day == d._day){return true;}elsereturn false;}int operator -( Date &d)  //计算日期差函数，重载“-”实现{int count = 0;Date tmp(*this);if (*this > d){tmp = d;d = *this;*this = tmp;}while (!(*this==d)){count++;*this =*this+1;}return count;}void print()       //打印函数{cout << _year << "-" << _month << "-" << _day;}int week()   //求出日期对应的星期函数{int w = 0;int y = _year;int m = _month;if (m == 1 || m == 2){m = _month + 12;y = _year - 1;}w = _day + 2 * m + 3 * (m + 1) / 5 + y + y / 4 - y / 100 + y / 400;w = w % 7 + 1;return w;}void print_week(){cout << "星期日 星期一 星期二 星期三 星期四 星期五 星期六" << endl;}void print_day()  //根据日期和星期，正确的输出日历{int line = 1;int days = GetMonthDay(_year,_day);int w = week();if (w != 7){for (int blank = w - 1; blank; --blank, ++line){cout << setw(7) << "";}}for (int d = 1; d <= days; ++d, ++line){cout << setw(7) << d;if (line % 7 == 0){cout << endl;}}cout << endl;}private:int _year;int _month;int _day;};void menu(){cout << setw(40) <<"万年历"<< endl;cout << "1.日期加减天数" << endl;cout << "2.日期减日期" << endl;cout << "3.输入年月显示当月日历" << endl;}void choice(){int num = 0;int year, month, day, days;char ch = '+';cin >> num;if (num == 1){cout << "请输入日期：" << endl;cin >> year >> month >> day;cout << "请输入天数:" << endl;cin >> days;cout << "请输入'+'或者'-':" << endl;cin >> ch;Date d1(year, month, day);Date d2;if (ch == '+'){d2 = d1 + days;}else if (ch == '-'){d2 = d1 - days;}else{cout << "无效的输入!" << endl;}cout << "计算后的日期为：";d2.print();cout << endl;}else if (num==2){cout << "请输入日期：" << endl;cin >> year >> month >> day;Date d3(year, month, day);cout << "请输入日期：" << endl;cin >> year >> month >> day;Date d4(year, month, day);int ret = d3 - d4;cout << "期间相差：" << ret << endl;}else if (num == 3){cout << "请输入年月:" << endl;cin >> year >> month;Date d5(year, month);d5.print_week();d5.print_day();}}int main(){menu();choice();system("pause");return 0;}