Date类的实现

╰半夏微凉° 2023-03-13 15:27 12阅读 0赞

**类与对象以及重载函数的运用：**  
ps:有几个需要注意的小点就直接注释在代码中了。

#### Date.h ####

#pragma once
    #include<iostream>
    using namespace std;
    
    class Date
    { 
    	friend ostream& operator<<(ostream& _cout, const Date& date);
    	friend istream& operator>>(istream& _cin, Date& date);
    public:
    	Date(int year, int month, int day); //构造
    	Date(const Date& d); //拷贝构造 d2(d1)
    	~Date();
    
    	Date& operator=(const Date& d);
    	Date& operator+=(int day); //日期 +=天数
    	Date  operator+(int day);  //日期 +天数
    	Date& operator-=(int day); //日期 -=天数
    	Date  operator-(int day);  //日期 -天数，不改变日期本身
    	Date& operator++();        //++date
    	Date  operator++(int);     //date++
    	Date& operator--();        //--date
    	Date  operator--(int);     //date--
    	bool operator == (const Date& d); // == 运算符重载
    	bool operator != (const Date& d); // != 运算符重载
    	bool operator >  (const Date& d); // > 运算符重载
    	bool operator >= (const Date& d); // >= 运算符重载
    	bool operator <  (const Date& d); // < 运算符重载
    	bool operator <= (const Date& d); // <= 运算符重载
    
    	int GetMonthDay(int year, int month);// 获取某年某月的天数
    	int operator-(const Date& d);//两个日期相差多少天
    	void Print()const; //打印
    private:
    	int _year;
    	int _month;
    	int _day;
    };

#### Date.cpp ####

#include"Date.h"
    
    
    bool LeapYear(int year)
    { 
    	return ((year % 4 == 0 && year % 100 != 0) || year % 400 == 0);
    }
    
    Date::Date(int year=1990, int month=1, int day=1) //构造
    { 
    	if (year > 0 && (month > 0 && month < 13) &&(day > 0 && day <= GetMonthDay(year, month)))
    	{ 
    		_year = year;
    		_month = month;
    		_day = day;
    	}
    	else 
    	{ 
    		cout << "the date is error!\n";
    	}
    }
    
    Date::Date(const Date& d)//拷贝构造 d2(d1) 
    {                         //必须传引用，防止递归调用拷贝构造函数
    	_year = d._year;
    	_month = d._month;
    	_day = d._day;
    }
    Date::~Date()
    { 
    
    }
    
    Date& Date::operator=(const Date& d) //赋值运算符重载,有深拷贝的时候(字符串)，必须显式定义
    { 
    	if (this != &d)   //避免自赋值
    	{ 
    		_year = d._year;
    		_month = d._month;        //传引用是为了减少调用拷贝构造函数
    		_day = d._day;
    	}
    	return *this;  //返回引用,而不是void,是为了可以实现连续赋值操作
    }
    
    Date& Date::operator+=(int day) //日期+=天数
    { 
    	if (day < 0)
    	{ 
    		return *this -= (-day);
    	}
    	_day += day;
    	while (_day > GetMonthDay(_year, _month))
    	{ 
    		_day -= GetMonthDay(_year, _month);
    		_month++;
    		if (_month > 12)
    		{ 
    			_year++;
    			_month -= 12;
    		}
    	}
    	return *this;
    }
    
    Date Date::operator+(int day)  //日期+天数
    { 
    	Date temp(*this);
    	temp += day;
    	return temp;
    }
    
    Date& Date::operator-=(int day) //日期-=天数
    { 
    	if (day < 0)
    	{ 
    		return *this += (-day);
    	}
    	_day -= day;
    	while (_day < 1)
    	{ 
    		_day += GetMonthDay(_year, _month);
    		_month--;
    		if (_month < 1)
    		{ 
    			_year--;
    			_month += 12;
    		}
    	}
    	return *this;
    }
    
    Date  Date::operator-(int day)  //日期-天数，不改变日期本身
    { 
    	Date temp(*this);
    	temp -= day;
    	return temp;
    }
    
    Date& Date::operator++()        //++date
    { 
    	*this += 1;
    	return *this;
    }
    
    Date  Date::operator++(int)     //date++
    { 
    	Date temp(*this);
    	*this += 1;
    	return temp;   //函数结束，栈帧销毁，不能返回引用
    }
    
    Date& Date::operator--()       //--date
    { 
    	*this -= 1;
    	return *this;
    }
    
    Date Date::operator--(int)    //date--
    { 
    	Date temp(*this);
    	*this -= 1;
    	return temp;
    }
    
    bool Date::operator == (const Date& d) // ==运算符重载
    { 
    	return (_year == d._year) && (_month == d._month) && (_day == d._day);
    }
    
    bool Date::operator != (const Date& d) // !=运算符重载
    { 
    	return (_year != d._year) || (_month != d._month) || (_day != d._day);
    }
    
    bool Date::operator >  (const Date& d) // >运算符重载
    { 
    	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 Date::operator >= (const Date& d) // >=运算符重载
    { 
    	return *this > d || *this == d;
    }
    
    bool Date::operator <  (const Date& d) // <运算符重载
    { 
    	return !(*this >= d);
    }
    
    bool Date::operator <= (const Date& d) // <=运算符重载
    { 
    	return !(*this > d);
    }
    
    int Date::GetMonthDay(int year, int month)// 获取某年某月的天数
    { 
    	static int days[13] = {  0, 31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31 };
    	int day = days[month];
    	if (month == 2 && LeapYear(year))
    	{ 
    		day += 1;
    	}
    	return day;
    }
    int Date::operator-(const Date& d)//两个日期相差多少天
    { 
    	Date maxDate(*this);
    	Date minDate(d);
    	if (maxDate < minDate) { 
    		maxDate = d;
    		minDate = *this;
    	}
    	int days = 0;
    	while (minDate + days < maxDate) 
    	{ 
    		days++;
    	}
    	return days;
    }
    
    void Date::Print()const //打印
    { 
    	cout << _year << "-" << _month << "-" << _day << endl;
    }
    
    ostream& operator<<(ostream& _cout, const Date& date)
    { 
    	_cout << date._year << "-" << date._month << "-" << date._day;
    	return _cout;
    }
    
    istream& operator>>(istream& _cin, Date& date)
    { 
    	_cin >> date._year >> date._month >> date._day;
    	return _cin;
    }

#### main.cpp ####

#include"Date.h"
    #include<Windows.h>
    
    void Test()
    { 
    	Date d(2020, 5, 15);
    
    	cout<<"d : " << d << endl<<endl;
    
    	cout <<"d+77 : "<< d + 77 << endl;
    	cout <<"d : "<< d << endl << endl;
    
    
    	cout <<"(d+=77) : "<< (d+=77) << endl;
    	cout << "d : " << d << endl << endl;
    
    	cout << "d-77 : " << d - 77 << endl;
    	cout << "d : " << d << endl << endl;
    
    
    	cout << "(d-=77) : " << (d -= 77) << endl;
    	cout << "d : " << d << endl << endl;
    
    	cout << "d++ : " << d++ << endl;
    	cout << "d : " << d << endl << endl;
    
    	cout << "++d : " << ++d << endl;
    	cout << "d : " << d << endl << endl;
    
    	cout << "d-- : " << d-- << endl;
    	cout << "d : " << d << endl << endl;
    
    	cout << "--d : " << --d << endl;
    	cout << "d : " << d << endl << endl;
    
    	Date d2(2020, 5, 15);
    	Date d3(2020, 8, 1);
    	cout << "d2-d3 : " << (d2 - d3) << endl;
    }
    
    int main()
    { 
    	Test();
    	system("pause");
    	return 0;
    }

敲的越多手越稳！