// Get valid date, print Julian 
#include <iostream>
using namespace std;
int days[13] = {0,31,28,31,30,31,30,31,31,30,31,30,31};
void getDate(int &m, int &d, int &y);
int julian(int m,int d, int y);
int main()
{ int month, day, year;
  getDate(month, day, year);
  cout<<month<<"/"<<day<<"/"<<year<<"\n";
  cout<<"It is the "<<julian(month,day,year)<<" day of the year.\n";
  return 0;
} // main 

bool leapyear(int year)
{  bool leap=false;
   if (year%4==0) leap=true; // if year not div. by 4, not leap year
   if ((year%100==0) && (year%400>0)) leap=false; // leap year if div by 400 
   return leap; //
} // leapyear
  
void getDate(int &mth, int &day, int &year)
{ bool valid=true;
  char ch;
  do
  {  cout<<"Enter date as mm/dd/yyyy: ";
     cin>>mth;
	 cin>>ch;
	 cin>>day;
	 cin>>ch;
	 cin>>year;
	 valid=true; //assume valid then reset if error found
	 if ((year<900) || (year > 3000))
     { cout<<"year must have 4 digits\n";
	   valid=false;
     } //check year
	 if (mth<1 || mth>12)
	 { cout<<"Month must be between 1 and 12\n";
	   valid=false;
     } //check month
	 if (valid)
     { if (day<1 || day>days[mth])
	 { cout<<"not a valid day\n";
	   valid=false;
	 }
     } //check day
      if (!valid) cout<<"Error, please reenter\n";
  } while (!valid);
} // getDate 

int julian(int month, int day, int year)
{ int total, m;
  leapyear(year);
  total=day;
  for (m=0;m<month-1;m++)
    total+=days[m];
  return total;
} // julian