#pragma once
#include<iostream>
#include<fstream>
using namespace std;
//第一种日期：以年/月/日（2020/6/27）的格式存储日期，可以进行加减法运算，但是减法不能出现负数，可以使用<<和>>实现文件操作。
class Date_1{
    int year;
    int month;
    int day;
public:
    Date_1(){ year = 0; month = 0; day = 0; }
    Date_1(int y,int m,int d){
        year=y;month=m;day=d;
    }
    //设置日期
    void Set(int y, int m, int d) {
        year = y; month = m; day = d;
    }
    friend Date_1 operator+(Date_1& a,Date_1&b){
        int ny, nm, nd;
        ny = a.year + b.year;
        nm = a.month + b.month;
        nd = a.day + b.day;
        if (ny % 4 == 0 && ny % 100 != 0 || ny % 400 != 0) {
            if (nm-1 == 1 || nm-1 == 3 || nm-1 == 5 || nm-1 == 7 || nm-1 == 8 || nm-1 == 10 || nm-1 == 12) {
                if (nd > 31) {
                    nm++;
                    nd = nd - 31;
                }
            }
            else if (nm-1 == 2) {
                if (nd > 29) {
                    nm++;
                    nd = nd - 29;
                }
            }
            else {
                if (nd > 30) {
                    nm++;
                    nd = nd - 30;
                }
            }
        }
        else {
            if (nm-1 == 1 || nm-1 == 3 || nm-1 == 5 || nm-1 == 7 || nm-1 == 8 || nm-1 == 10 || nm-1 == 12) {
                if (nd > 31) {
                    nm++;
                    nd = nd - 31;
                }
            }
            else if (nm-1 == 2) {
                if (nd > 28) {
                    nm++;
                    nd = nd - 28;
                }
            }
            else {
                if (nd > 30) {
                    nm++;
                    nd = nd - 30;
                }
            }
        }
        if (nm > 12) {
            ny++;
            nm = nm - 12;
        }
        return Date_1(ny,nm,nd);
    }
    friend Date_1 operator-(Date_1& a,Date_1&b){
        if(a.day<b.day||a.month<b.month||a.day<b.day){
            cout<<"运算错误：结果为负，请确认两个操作数的差不是负数！"<<endl;
            cout<<"Error:The result is negative.Please make sure the difference between the two operands is not negative!"<<endl;
            cout<<"Ошибка операции:результат отрицательный.Убедитесь,что разница между двумя операндами не является отрицательной!"<<endl;
            return Date_1(0,0,0);
        }else{
            return Date_1(a.day-b.day,a.month-b.month,a.day-b.day);
        }
    }
    friend ostream& operator<<(ostream &a,Date_1 &d) {
        a << d.year << "/" << d.month << "/" << d.day;
        return a;
    }
    friend istream& operator>>(istream &a,Date_1 &d) {
        a >> d.year;
        a.get();
        a >> d.month;
        a.get();
        a >> d.day;
        return a;
    }
    friend ofstream& operator<<(ofstream& a, Date_1& d) {
        a << d.year << noskipws << " " << d.month << noskipws << " " << d.day;
        return a;
    }
    friend ifstream& operator>>(ifstream& a, Date_1& d) {
        a >> d.year;
        a.get();
        a >> d.month;
        a.get();
        a >> d.day;
        return a;
    }
    friend fstream& operator<<(fstream& a, Date_1& d) {
        a << d.year << noskipws << " " << d.month << noskipws << " " << d.day;
        return a;
    }
    friend fstream& operator>>(fstream& a, Date_1& d) {
        a >> d.year;
        a.get();
        a >> d.month;
        a.get();
        a >> d.day;
        return a;
    }
};
//第二种日期：以月/日/年（6/27/2020）的格式存储日期，可以进行加减法运算，但是减法不能出现负数，不可以使用<<和>>实现文件操作。
class Date_2{
    int year;
    int month;
    int day;
public:
    Date_2() { year = 0; month = 0; day = 0; }
    Date_2(int y,int m,int d){
        year=y;month=m;day=d;
    }
    friend Date_2 operator+(Date_2& a,Date_2&b){
        int ny, nm, nd;
        ny = a.year + b.year;
        nm = a.month + b.month;
        nd = a.day + b.day;
        if (ny % 4 == 0 && ny % 100 != 0 || ny % 400 != 0) {
            if (nm - 1 == 1 || nm - 1 == 3 || nm - 1 == 5 || nm - 1 == 7 || nm - 1 == 8 || nm - 1 == 10 || nm - 1 == 12) {
                if (nd > 31) {
                    nm++;
                    nd = nd - 31;
                }
            }
            else if (nm - 1 == 2) {
                if (nd > 29) {
                    nm++;
                    nd = nd - 29;
                }
            }
            else {
                if (nd > 30) {
                    nm++;
                    nd = nd - 30;
                }
            }
        }
        else {
            if (nm - 1 == 1 || nm - 1 == 3 || nm - 1 == 5 || nm - 1 == 7 || nm - 1 == 8 || nm - 1 == 10 || nm - 1 == 12) {
                if (nd > 31) {
                    nm++;
                    nd = nd - 31;
                }
            }
            else if (nm - 1 == 2) {
                if (nd > 28) {
                    nm++;
                    nd = nd - 28;
                }
            }
            else {
                if (nd > 30) {
                    nm++;
                    nd = nd - 30;
                }
            }
        }
        if (nm > 12) {
            ny++;
            nm = nm - 12;
        }
        return Date_2(ny, nm, nd);
    }
    friend Date_2 operator-(Date_2& a,Date_2&b){
        if(a.day<b.day||a.month<b.month||a.day<b.day){
            cout<<"运算错误：结果为负，请确认两个操作数的差不是负数！"<<endl;
            cout<<"Error:The result is negative.Please make sure the difference between the two operands is not negative!"<<endl;
            cout<<"Ошибка операции:результат отрицательный.Убедитесь,что разница между двумя операндами не является отрицательной!"<<endl;
            return Date_2(0,0,0);
        }else{
            return Date_2(a.day-b.day,a.month-b.month,a.day-b.day);
        }
    }
    friend ostream& operator<<(ostream &a,Date_2 &d) {
        a << d.month << "/" << d.day << "/" << d.year;
        return a;
    }
    friend istream& operator>>(istream& a, Date_2& d) {
        a >> d.month >> d.day >> d.year;
        return a;
    }
    void Set(int y, int m, int d) {
        year = y; month = m; day = d;
    }
};
//第三种日期：以月（英文） 日 年（Jun. 27 2020）的格式存储日期，可以进行加减法运算，但是减法不能出现负数，不可以使用<<和>>实现文件操作。
class Date_3{
    int year;
    int month;
    int day;
    public:
        Date_3() { year = 0; month = 0; day = 0; }
    Date_3(int y,int m,int d){
        year=y;month=m;day=d;
    }
    friend Date_3 operator+(Date_3& a,Date_3&b){
        int ny, nm, nd;
        ny = a.year + b.year;
        nm = a.month + b.month;
        nd = a.day + b.day;
        if (ny % 4 == 0 && ny % 100 != 0 || ny % 400 != 0) {
            if (nm - 1 == 1 || nm - 1 == 3 || nm - 1 == 5 || nm - 1 == 7 || nm - 1 == 8 || nm - 1 == 10 || nm - 1 == 12) {
                if (nd > 31) {
                    nm++;
                    nd = nd - 31;
                }
            }
            else if (nm - 1 == 2) {
                if (nd > 29) {
                    nm++;
                    nd = nd - 29;
                }
            }
            else {
                if (nd > 30) {
                    nm++;
                    nd = nd - 30;
                }
            }
        }
        else {
            if (nm - 1 == 1 || nm - 1 == 3 || nm - 1 == 5 || nm - 1 == 7 || nm - 1 == 8 || nm - 1 == 10 || nm - 1 == 12) {
                if (nd > 31) {
                    nm++;
                    nd = nd - 31;
                }
            }
            else if (nm - 1 == 2) {
                if (nd > 28) {
                    nm++;
                    nd = nd - 28;
                }
            }
            else {
                if (nd > 30) {
                    nm++;
                    nd = nd - 30;
                }
            }
        }
        if (nm > 12) {
            ny++;
            nm = nm - 12;
        }
        return Date_3(ny, nm, nd);
    }
    friend Date_3 operator-(Date_3& a,Date_3&b){
        if(a.day<b.day||a.month<b.month||a.day<b.day){
            cout<<"运算错误：结果为负，请确认两个操作数的差不是负数！"<<endl;
            cout<<"Error:The result is negative.Please make sure the difference between the two operands is not negative!"<<endl;
            cout<<"Ошибка операции:результат отрицательный.Убедитесь,что разница между двумя операндами не является отрицательной!"<<endl;
            return Date_3(0,0,0);
        }else{
            return Date_3(a.day-b.day,a.month-b.month,a.day-b.day);
        }
    }
    friend ostream& operator<<(ostream &a,Date_3 &d) {
        string month[12] = { "Jan.","Feb.","Mar.","Apr.","May","Jun.","Jul.","Aug.","Sep.","Oct.","Nov.","Dec." };
        a << month[d.month - 1] << noskipws << " " << d.day << noskipws << " " << d.year;
        return a;
    }
    friend istream& operator>>(istream &a,Date_3 &d) {
        a >> d.month >> d.day >> d.year;
        return a;
    }
    void Set(int y, int m, int d) {
        year = y; month = m; day = d;
    }
};