c++:日历的实现

             这次日期类的实现呢，主要具备查某月的日历，日期加减天数后是哪一天，两个日期之间相差的天数。比如说：你想知道离开学的日子还有多少天啊，离我们找工作还有多少天呐，这个月的日历是什么样的啊都可以它来查询！

下面给出代码实现：

Date.h

#ifndef _DATE__H_
#define _DATE__H_
#include<cstdio>
#include<iostream>
using namespace std;
class Date
{
 friend void PrintDate(int year,int month);
public:
 Date(int year,int month,int day);
 Date(const Date& d);
      
 bool JudgeLeapyear(int year)const;
 int SetDay(const Date& d);       //设置每月的天数并返回是哪个月
 Date operator+(int day);        //日期加天数
 Date operator-(int day);       //日期减天数
 int operator-(const Date& date);   //日期减日期(相差天数)
 int Week(int year,int month);     //计算当前月的第一天是星期几
 void Display();
 bool operator==(const Date& d);
 bool operator>(const Date& d);
 Date& operator=(const Date& d);
private:
 int _year;
 int _month;
 int _day;
};
void PrintDate(int year,int month);//打印该月日历
#endif   //_DATE__H_



Date.cpp
#include"Date.h"
Date::Date(int year=1990,int month=1,int day=1)
 :_year(year),
 _month(month),
 _day(day)
{
 if(month>12 ||day>SetDay(*this))
 {
    cout<<"输入日期不合法！"<<endl;
 }
}
Date::Date(const Date& d)
{
 _year=d._year;
 _month=d._month;
 _day=d._day;
}  
bool Date::JudgeLeapyear(int year)const
{
 if(((year%4==0)&&(year%100!=0))||(year%400==0))
 {
  return true;
 }
 else
 {
  return false;
 }
}
int Date::SetDay(const Date& d)
{
 int month[13]={0,31,28,31,30,31,30,31,31,30,31,30,31};
 if(JudgeLeapyear(d._year))
 {
  month[2]=29;
 }
 return month[d._month];         //返回是哪个月
}
bool Date::operator>(const Date& d)
{
 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;
   }
   else
    return false;
  }
  else
   return false;
 }
 else
  return false;
}
bool Date::operator==(const Date& d)
{
 if(_year==d._year && _month==d._month && _day==d._day)
 {
  return true;
 }
 else
 {
  return false;
 }
}
Date& Date::operator=(const Date& d)
{
 if(*this==d)
 {
  return *this;
 }
 _year=d._year;
 _month=d._month;
 _day=d._day;
 return *this;
}
Date Date::operator+(int day)        //日期加天数
{
 _day=_day+day;
 while(_day > SetDay(*this))
 {
  _day=_day-SetDay(*this);
  _month++;
  if(_month>12)
  {
   _month=_month-12;
   _year++;
  }
 }
 return *this;
}
Date Date::operator-(int day)       //日期减天数
{
 _day=_day-day;
 while(_day<=0)
 {
  _month--;
  if(_month<=0)
  {
   _month=_month+12;   
   _year--;
  }
  _day=_day+SetDay(*this);
 }
 return *this;
}
int Date::operator-(const Date& date)   //日期减日期
{
 int days=0;     //统计相差几天
 Date small(*this);
 Date big(date);
 if(*this>date)
 {
  big=*this;
  small=date;
 }
 while(big._year>small._year)
 {
  if(JudgeLeapyear(small._year))
  {
   days=days+366;
  }
  else
  {
   days=days+365;
  }
  small._year++;
 }
 while(small._month>big._month)
 {
  days=days-SetDay(small);
  small._month--;
 }
 while(big._month>small._month)
 {
  days=days+SetDay(small);
  small._month++;
 }
 days=days+(big._day-small._day);
 if(*this>date)
 {
  return -days;
 }
 else
  return days;
}
int Date::Week(int year,int month)
{
 if(year>=1600 && month>=1)
 {
  int week=6;    //日历从1600.1.1开始该天是周六
  int day=0;
  Date d1(1600,1,1);
  Date d2(year,month,1);
  day=d1-d2;  //统计目标月份与起始月份相差的天数
  week=day%7+week;
  if(week>7)
  {
   week=week-7;
  }
  return week;
 }
 return -1;
}
void PrintDate(int year,int month)
{
 int i=0;   //控制最多输出行
 int j=0;   //控制列
 int day=1;
 Date d(year,month,1);
 int week=d.Week(year,month);
 if(week!=-1)
 {
  cout<<year<<"年"<<month<<"月"<<endl;
  cout<<"日"<<" "<<"一"<<" "<<"二"<<" "<<"三"<<" "<<"四"<<" "<<"五"<<" "<<"六"<<" "<<endl;
     for(j=0;j<week;j++)
     {
    cout<<" ";
     }
     for(i=0;i<6;i++)
  {
   for(j=week;j<7;j++)
    {
   if(day<=d.SetDay(d))
   {
    printf("%3d",day);
    day++;
   }
   else
    break;
     }
   cout<<endl;
   week=0;
  }
 }
 else
  return;
}
void Date::Display()
{
 cout<<_year<<"-"<<_month<<"-"<<_day<<endl;
}



test.cpp
#include"Date.h"
void test1()     //加减天数
{
 Date d1(2014,9,1);
 d1.Display();
 Date d2=d1+21;
 d2.Display();
 Date d3=d1+60;
 d3.Display();
 //Date d4=d1-50;
 //d4.Display();
}
void test2()
{
 int ret;
 Date d1(2011,1,2);
 d1.Display();
 Date d2(2016,1,1);
 d2.Display();
 ret=d1-d2;
 cout<< "相差天数："<<ret<<endl;
}
void test3()
{
 int year=0;
 int month=0;
 printf("%d%d",&year,&month);
 PrintDate(year,month);
}
int main()
{
 //test1();
 //test2();
 test3();
 system("pause");
 return 0;
}