运算符重载实现日期推算

#include<iostream> using namespace std; class Date { public: int GetMonthDay(int year, int month) { static int days[13]={0,31,28,31,30,31,30,31,31,30,31,30,31}; int day = days[month]; if((month == 2)&&(((year % 4 == 0)&&(year % 100 != 0))||(year%400 ==0))) { day+=1; } return day; } Date(int year = 2000, int month = 1, int day = 1) { _year = year; _month = month; _day = day; } Date(const Date& d)//拷贝构造函数 { _year = d._year; _month =d._month; _day = d._day; } Date& operator+=(int day)//+=运算符重载 { if(day < 0) { return *this -= -day; } _day += day; while(_day > GetMonthDay(_year,_month)) { _day -=GetMonthDay(_year,_month); _month++; if(_month == 13) { _year++; _month = 1; } } return *this; } Date& operator-=(int day)//-=运算符重载 { if(day < 0) { return *this += -day; } _day -= day; while(_day < 0) { _month--; if(_month == 0) { _year--; _month = 12; } _day +=GetMonthDay(_year,_month); } return *this; } Date& operator=(const Date& d)//赋值运算符重载 { if(this !=&d) { _year = d._year; _month = d._month; _day = d._day; } } Date& operator++()//前置++运算符重载 { *this+=1; return *this; } Date operator++(int)//后置++运算符重载 { Date ret(*this); *this +=1; return ret; } bool operator<(const Date& d) { if(_year < d._year) { return 1; } else if (_year == d._year) { if(_month < d._month) { return 1; } else if(_month == d._month) { if(_day < d._day) { return 1; } else { return 0; } } else { return 0; } } else { return 0; } } int operator-(const Date&d)//-运算符重载，用于计算日期差 { Date max = *this; Date min = d; if(*this < d) { max = d; min = *this; } int day =0; while(min <max) { ++(min); ++day; } return day; } int _year; int _month; int _day; }; int main() { //Date d1(2024,9,5); int i,j,k; cout <<"请输入初始日期的年"<<'\n'; cin>>i; cout <<"请输入初始日期的月"<<'\n'; cin>>j; cout <<"请输入初始日期的日"<<'\n'; cin>>k; Date d1(i,j,k); cout <<"您输入的日期为:"<<'\t'<< d1._year << '-' << d1._month << '-' << d1._day <<endl; int select; cout <<"请输入需要进行的操作"<<'\n'; cout <<"1.日期加运算"<<'\n'; cout <<"2.日期减运算"<<'\n'; cout <<"3.计算日期差"<<'\n'; cin >>select; if(select == 1) { int day1; cout <<"请输入需要加的天数"<<endl; cin >> day1; d1+=day1; cout << d1._year << '-' << d1._month << '-' << d1._day <<endl; } else if (select ==2) { int day2; cout <<"请输入需要减的天数"<<endl; cin >> day2; d1-=day2; cout << d1._year << '-' << d1._month << '-' << d1._day <<endl; } else if(select == 3) { int i1,j1,k1; cout <<"请输入目标日期年"<<'\n'; cin>>i1; cout <<"请输入目标日期月"<<'\n'; cin>>j1; cout <<"请输入目标日期日"<<'\n'; cin>>k1; Date d2(i1,j1,k1); cout <<"您输入的日期为:"<<'\t'<< d2._year << '-' << d2._month << '-' << d2._day <<endl; int ret = d1-d2; cout <<"两个日期只差为："<<' ' << ret << "天" <<endl; } else { cout << "您的输入有误"<<endl; } return 0; }