anyone knows the code for this c++ question?

[i like c++]

The Julian calendar consist of a solar year of 12 months and of 365 days withan extra day every four years.

In the Gregorian calendar a year is a leap year if either
1)it is divisible by 4 but not 100 or
2)it is divisible by 100

Using the gregorian calendar, in 1752, (wednesday) september 2 1752 is such that is followed immediately by september 14 1752.

Most computers use the Julian calendar until september 1752, with leap year every four years , then use the Gregorian calendar after that.

1/1/1 falls on a saturday.

Need to construct an ADT for calendar with class "Date" which follow the specifications above.

Need to have the various construtors and functions below:

Date()//initialise to 1/1/1
Date(DD,MM,YYYY)//initialise date to DD/MM/YYYY
next()//To set the date such that it advance the day by 1 day.
printD()//print out day of week(eg.monday, tuesday ,......)
printT()//print out day in the form DD/MM/YYYY.
printW()//print out day in the form such as 12 March 1782.
diffD(D)//print out the absolute number of days between the current date and the and D.

The calendar only work for date from 1/1/1 to 31/12/9999.

Thank you very much!

[redhead]

We're not here to solve your assignments, we will how ever provide you with help, if you get stuck and show us what code you've got so far..
Anyway, a google search on the subject: "a leap year test written in c"
Will provide you with enough info to get started, just pick the first item on the list.

[i like c++]

Here is my code, but its very long and i'm not sure how to shorten it.

//Set current variable.
void Date::Date(int DD, int MM, int YYYY){
  date=DD;
  month=MM;
  year=YYYY;
}

//Next date for the current variable.
void Date::next(){
  if(date<28)
  date+=1;
  else{
    switch(month){
      //Compare the month.
      case '1':if(date==31){
                 date=1;
                 month=2;               
               }               
               else
                 date+=1;
               break;  
      case '2':if(year<=1752){       //For years following Julian calendar.
                 if(year%4==0){     //Leap year.
                   if(date==29){
                     date=1;
                     month=3;
                   }
                   else
                   date+=1;
                 }
                 else{
                   date=1;
                   month=3;
                 }      
               }                                
               if(year>1752 && year<=9999){     //For year following the Gregorian calendar.
                 if((year%4==0 && year%1000!=0) || year%400==0){   //Leap year.
                   if(date==29){
                     date=1;
                     month=3;
                   }
                   else                   
                   date+=1;
                 }
                 else{
                   date=1;
                   month=3;
                 }        
               }
               break;
      case '3':if(date==31){
                 date=1;
                 month=4;               
               }
               else
                 date+=1;
               break; 
      case '4':if(date==30){
                 date=1;
                 month=5;               
               }
               else
                 date+=1;
               break;  
      case '5':if(date==31){
                 date=1;
                 month=6;               
               }
               else
                 date+=1;
               break;  
      case '6':if(date==30){
                 date=1;
                 month=7;              
               }
               else
                 date+=1;
               break;  
      case '7':if(date==31){          
                 date=1;
                 month=8;                     
               }              
               else
                 date+=1;
               break;  
      case '8':if(date==31){
                 date=1;
                 month=9;               
               }
               else
                 date+=1;
               break;  
      case '9':if(year==1752 && date==2){    
          //Special case in september 1972.
                   date=14;                 
               }
               else{
                 if(date==30){
                   date=1;
                   month=10;               
                 }
                 else
                   date+=1;  
               }
               break;  
      case '10':if(date==31){
                 date=1;
                 month=11;               
               }
               else
                 date+=1;
               break;  
      case '11':if(date==30){
                 date=1;
                 month=2;               
               }
               else
                 date+=1;
               break;  
      case '12':if(date==31){
                 date=1;
                 month=1;
                 if(year<9999)
                 year+=1;
               }
               else
                 date+=1;
               break;  
    }//End of switch loop.      
  }//End of else.
}

//Print out variable day of week.
void printD(){
  int tempDate, tempMonth, tempYear, k, numOfDays=0;//Local declarations.
  tempDate=date;
  tempMonth=month;
  tempYear=year;
  date=1;
  month=1;
  year=1;
  
  while(tempDate!=date && tempMonth!=month && tempYear!=year){
     next();
     numOfDays++;
  }//End of while loop.

  k=numOfDays%7;  
  switch(k){
    case '0':cout << "Saturday";
    case '1':cout << "Sunday";
    case '2':cout << "Monday";
    case '3':cout << "Tuesday";
    case '4':cout << "Wednesday";
    case '5':cout << "Thursday";
    case '6':cout << "Friday";  
  }//End of switch.
  
  date=tempDate;
  month=tempMonth;
  year=tempYear;
  if(date==1 && month==1)
    cout << " (New Year's Day)";//If that day is a new year.
  if(date=14 && month==2)
    cout << " (Valentine's Day)";//If that day is a valentine's day.
  cout << endl;
}//End of printD function.

//Print out variable as DD/MM/YYYY.
void printT(){
  cout << date << "/" << month << "/" << year << endl;
}//End of printT function.

//Print out variable in the form of 28 March 2004;
void printW(){
  cout << date;
  //Compare month.
  switch(month){
    case '1':cout << " January ";
    case '2':cout << " FebRuary ";
    case '3':cout << " March ";
    case '4':cout << " April ";
    case '5':cout << " May ";
    case '6':cout << " June ";
    case '7':cout << " July ";
    case '8':cout << " August ";
    case '9':cout << " September ";
    case '10':cout << " October ";
    case '11':cout << " November ";
    case '12':cout << " December ";
  }//End of switch.
  cout << year << endl;
}//End of printW function.

//Print out the absolute number of days between current date and a particular date, D.
void diff(int theDate, int theMonth, int theYear){
int tempDate, tempMonth, tempYear, k,difference, numOfDays=0;//Local declarations.
  tempDate=date;
  tempMonth=month;
  tempYear=year;
  if(theDate>=date && theMonth>=month && theYear>=year){
     // If current date is earlier than or same as D.
    while(date!=theDate && month!=theMonth && year!=theYear){
      next();
      numOfDays++;  
    }//End of while loop.
    if(numOfDays>=1)
      difference=numOfDays-1;
    else
      difference=numOfDays;
    cout << difference << endl;
    date=tempDate;
    month=tempMonth;
    year=tempYear;
  }
  else{       //If d is earlier than current date.
    date=theDate;
    month=theMonth;
    year=theYear;
    while(date!=tempDate && month!=tempMonth && year!=tempYear){
      next();
      numOfDays++;  
    }
    if(numOfDays>=1)
      difference=numOfDays-1;
    else
      difference=numOfDays;
    cout << difference << endl;
    date=tempDate;
    month=tempMonth;
    year=tempYear;  
  }
}//End of diff function.

[Valmont]

You can easely optimize the leap year function:

bool is_leap_year(int year)
{
      if( year % 4 ) return false;  
      if( year < ReformYear ) return true; 
      if( year % 100 ) return true; 
      if( year % 400 ) return false;      
      return true;
}

But what exactly is it that you need us for? What is the concrete question or request?

[i like c++]

I don't really get what you meant. Do you meant why am i asking the question here or....?

[Valmont]

My question is: how can we help you exactly?

[i like c++]

I think there are logic errors in the code that i posted out because the output that i got using the code did not give me the correct outputs. Thank you for your help!

[Valmont]

First things first. Learn to design a decent class first. The math behind all this is hard enough. So let's setup a decent class and then see if you can manage it from here. If not, then feel free to come back.

Date.h

#ifndef DATE_H
#define DATE_H

#include <ctime>

class Date
{
public:
  enum month
  {jan = 1, feb, mar, apr, may, jun, jul, aug, sep, oct, nov, dec };
  enum week_day
  { mon = 1, tue, wed, thu, fri, sat, sun  };
  static const int REFORM_YEAR;
  static const month REFORM_MONTH;
  static const unsigned REFORM_DAY_NUMBER;
public: //Ctors et al. only.
  Date();
  Date(month, int, int);
public: //Accessors only.
  int get_year() const;
  int get_day() const;
  month get_month() const;
public:
  static int days_in_month(month, int);
  static bool is_leap(int);
protected:
  void set_date(month, int, int);
  unsigned long calc_day_number() const;
private:
  month month_;
  int   day_;
  int   year_;
  unsigned long daynumber_;
};

/***************** inlines ***************/

inline int Date::get_year() const
{
  return year_;
}
//-----------------------------------------
inline int Date::get_day() const
{
  return day_;
}
//-----------------------------------------
inline Date::month Date::get_month() const
{
  return month_;
}
//-----------------------------------------

#endif //DATE_H

Date.cpp

#include "Date.h"

const int Date::REFORM_YEAR = 1582;
const unsigned Date::REFORM_DAY_NUMBER = 577737L;
const Date::month Date::REFORM_MONTH  = Date::oct;

//-----------------------------------------------------

Date::Date()
{
  set_date(jan, 1, 1);
}

//-----------------------------------------------------

Date::Date(month m, int d, int y)
{
  set_date(m, d, y);
}

//-----------------------------------------------------

void Date::set_date(month m, int d, int y)
{
  month_ = m;
  day_   = d;
  year_  = y;
  daynumber_ = calc_day_number();
}

//----------------------------------------------------

bool Date::is_leap(int yr)
{
  if( yr % 4 ) return false;
  if( yr < REFORM_YEAR ) return true;
  if( yr % 100 ) return true;
  if( yr % 400 ) return false;
  return true;
}

//-----------------------------------------------------

int Date::days_in_month(month mth, int yr)
{
  static const int days[13] = {0,31,28,31,30,31,30,31,31,30,31,30,31};
  if( yr == REFORM_YEAR && mth == REFORM_MONTH )
  {
    return 21;
  }
  return days[mth] + (feb == mth && is_leap(yr));
}

//-----------------------------------------------------

unsigned long Date::calc_day_number() const
{
  long days;
  long year  = (long)year_ - 1L;
  days = year * 365L + year / 4L - year / 100L + year / 400L;
  //Years before 1582 were all leap if it is divisible by 4.
  if( year > REFORM_YEAR )
  {
    days += 12;
  }
  else
  {
    days += year / 100L;
    days -= year / 400L;
  }
  for( int i = jan; i < month_; ++i )
  {
    days += days_in_month((month)i, year_);
  }
  days += day_;
  //Adjust for the 10 missing days (Oct 4 - Oct 15, 1582).
  if( days > REFORM_DAY_NUMBER )
  {
    days -= 10L;
  }
  
  return days;
}

main.cpp

#include "Date.h"
#include <iostream>

using namespace std;

int main(int argc, char *argv[])
{
  Date dt;
  cout << dt.get_day() << " " << dt.get_month() << " " << dt.get_year() << endl;
  
  cin.get();
  return 0;
}

The calc_day_number() method is your key to success if you want to implement the next_day() function.
Here are the global steps:
1) Implement an overloaded operator+().
2) Implement a method that calculates the total amount of days added with the number of days you want. Make it calculate the year, month and day.

For example if day_number is day_number+1, then check if the resulting day_number > refordaynumber. If it is, then add 10 days to the resulting day_number! That is because there are 10 days missing because pope Gregor XXLLLCXXX (or something) reformed it.

3) The year_ is then obviously: (int)daynumber_ / 365. Duh.
4) The day_ is INITIALLY: (int)daynumber_ % 365L. Convince your self!
5) Adjust the initial day IF resulting years_ < 1700.
6) And/Or adjust the initial day_, taking leap years into account.

Etcetera etcetera. I needed to study for this too. And now I want a break. See how far you can get. Be welcome anytime. But beware, I do not like lazy folks.