/*  通过输入年月日，计算出这一天是星期几，计算这一天是这一年的多少天，判断这一年是否为闰年  */  #include<iostream>  using namespace std;    struct time  {  int year;  int month;  int day;  unsigned int weekday;  };    void initialtime(time & t);//输入初始化时间  void Show(time & t);//显示时间信息  int Weekdaycount(time & t);//计算当日是星期几  int Daycount(time & t);//计算当日是第公元多少天  int Daysyearcount(time & t);//计算当日是该年的第多少天  bool isleapyear(time & t);//判断该年是不是闰年  bool check(time &t);//检查时间格式是否正确    int main()  {  time t;  initialtime(t);  Show(t);  return 0;  }    bool check(time &t)  {  if (t.year <= 0 || (t.month <= 0 || t.month>12) || t.day <= 0) return false;  else{  if ((t.month == 1 || t.month == 3 || t.month == 5 || t.month == 7  || t.month == 8 || t.month == 10 || t.month == 12) && t.day > 31)return false;  else  {  if ((t.month == 4 || t.month == 6 || t.month == 9 || t.month == 11  ) && t.day > 30)return false;  else  {  if (t.month == 2) {  if (isleapyear(t)) {  if (t.day > 29)return false; else return true;  }  else  {  if (t.day > 28)return false; else return true;  }  }  }  }  }  }  void initialtime(time & t)  {  cout << "Enter the time (year,month,day):\n";  cin >> t.year;  cin.get();  cin>> t.month;  cin.get();  cin >> t.day;  cin.get();  if (!check(t)){ cout << "Try again:\n"; initialtime(t); }  else  t.weekday = Weekdaycount(t);  }  void Show(time & t)  {  cout << "Year: " << t.year << "\t";  cout << "Month: " << t.month << "\t";  cout << "Day: " << t.day << "\t";  cout << "Weekday: " << t.weekday << endl;  cout << "This is a ";  if (isleapyear(t))cout << "leap"; else cout << "nonleap";  cout << " year.\n";  cout << "Today is the " << Daysyearcount(t) << " days of the year.\n";  }  int Weekdaycount(time & t)  {  return Daycount(t) % 7;  }  int Daycount(time & t)  {  int days = 0;  days = (t.year - 1) * 365 + (t.year - 1) / 4 - (t.year - 1) / 100  + (t.year - 1) / 400 + Daysyearcount(t);  return days;  }  bool isleapyear(time & t)  {  if (t.year % 4 == 0 && t.year % 100 != 0) return true;//年是四的倍数而且不是100的倍数，是闰年  if (t.year % 400 == 0)return true;  else return false;  }  int Daysyearcount(time & t)  {  int days = 0;  int mtemp = t.month - 1;  while (mtemp > 0)  {  switch (mtemp)  {  case(1) :  case(3) :   case(5) :   case(7) :   case(8) :   case(10) :   case(12) :  days += 31; break;  case(4):  case(6):  case(9):   case(11):  days += 30; break;  case(2) :  days += 28; break;  default:  break;  }  --mtemp;  }  if (isleapyear(t))++days;//如果是闰年，再加上一天  return days+t.day;//返回计算的天数加上当月的天数  }