#include<iostream>
using namespace std;
int daynum[13]={0,31,0,31,30,31,30,31,31,30,31,30,31};
//daynum[1]~daynum[12]分別為一年各月的天數 
class date
{
 private:
 int year,month,day,week;
 public:
 void input(int y,int m,int d);//輸入
 int testerror(int select);    //輸入的錯誤檢查
 void showdate(int select);    //輸出年歷、月歷或日歷
};

void date::input(int y,int m,int d)
{
 year=y; month=m; day=d;
}
int date::testerror(int select)
{
  if((year%4==0&&year%100!=0)||(year%400==0))
    daynum[2]=29;  //閏年2月有29天
  else
    daynum[2]=28;  //非閏年2月有28天
  if(year<1||year>9999) 
  {
	 cout<<"年輸入錯誤!\n\n"; return 1;
  }
  if(month<1||month>12&&select!=3) 
  {
	 cout<<"月輸入錯誤!\n\n"; return 1;
  }
  if(day<1||day>daynum[month]&&select==1)
  {
	 cout<<"日輸入錯誤!\n\n"; return 1;
  }
  return 0;    //輸入正確    
 }
void date::showdate(int select)
{
 int i,k,dnum;     //dnum為公元1年1月1日至輸入的年月日時的總天數
 int leapyear=0;   //0表示當年不是閏年
 dnum=(year-1)*365+1;
 for(k=1;k<year;k++)
  if((k%4==0&&k%100!=0)||(k%400==0))
 	  dnum++;
 if(select==1) //以下輸出日歷
 {
  for(k=1;k<month;k++)
   dnum=dnum+daynum[k];
  dnum=dnum+day-1;
  cout<<"==================\n公元"<<year<<"年"<<month<<"月"<<day<<"日\n";
  if(dnum%7==0)
   cout<<"     星期日"<<endl;
  else
   switch(dnum%7){
   case 1: cout<<"     星期一"<<endl;break;
   case 2: cout<<"     星期二"<<endl;break;
   case 3: cout<<"     星期三"<<endl;break;
   case 4: cout<<"     星期四"<<endl;break;
   case 5: cout<<"     星期五"<<endl;break;
   case 6: cout<<"     星期六"<<endl;break;
  }
  cout<<"==================\n\n";
 } //if
 else //以下輸出年歷或月歷
 {
  if(select==3)  //年歷
   cout<<"==================================\n    ******公元"<<year<<"年年歷******\n==================================";
  if(select==2)  //日歷
  { for(k=1;k<month;k++)
      dnum=dnum+daynum[k];
    if(leapyear==1&&month>2)
      dnum++;
    cout<<"==================================\n   ******公元"<<year<<"年"<<month<<"月月歷******\n==================================";
  }
  week=dnum%7; 
  for(i=1;i<=12;i++) // i為月份
  {
   if(select==2)     //select=2時只輸出month月的月歷
    i=month;
   cout<<"\n\n"<<i<<"月  sun mon tue wed thu fri sat\n";
   for(k=0;k<6+4*week;k++)
	  cout<<" ";
   for(k=1;k<=daynum[i];k++)
   {
    if((week+k)%7==1&&k!=1)
	{
	 cout<<"\n      ";
	}
	cout<<k<<"  ";
	if(k<10)
	  cout<<" ";
   }//for k
   week=(week+daynum[i])%7;
   cout<<"\n\n==================================\n----------------------------------";
   if(select==2)    
    break;      //select=2時只輸出month月的月歷
  }//for i
  cout<<"\n\n";
 }//else 
}
void main()
{
 int year,month,day;
 int t;
 int select;
 date d;
 cout<<"------------------\n   1、輸出日歷；\n   2、輸出月歷；\n   3、輸出年歷;\n   0、退出。\n-----------------\n";				  \
 while(1)
 {
	 cout<<"請選擇(0--3): ";
	 while(!(cin>>select))
	 {
        cout<<"error:輸入非數字!\n";//若select為非數字則出錯提示
		cin.clear();            //清除狀態位
		cin.ignore(INT_MAX, '\n');
	 }
	
	if(select==1)		 
	{
	 cout<<"請輸入 年(1—9999)月日: \n";
	 cin>>year>>month>>day;
	 d.input(year,month,day);
     t=d.testerror(select); // 輸入檢查
 	}
    
	if(select==2)		  
	{
	  cout<<"請輸入 年(1—9999)月: \n";
	  cin>>year>>month;
	  d.input(year,month,1); 
	  t=d.testerror(select);// 輸入檢查
	}
	
	if(select==3)         
	{
	  cout<<"請輸入年份(1—9999): \n";
	  cin>>year;
	  d.input(year,1,1);
      t=d.testerror(select);// 輸入檢查
	}
    
    if(select==0)		 //0 退出
	{ 
	  cout<<"******Thank you for using!******\n";
	  break;   
    }
	
	if(select!=0&&select!=1&&select!=2&&select!=3)
	{
	  cout<<"\n選擇錯誤,請重新選擇!\n\n";
	  continue;
	}
	if(t==0)			 //輸入無錯則輸出年歷，月歷或日歷	
     d.showdate(select);

 }//while(1)
}