asked on

use of an overloaded operator of class date

I have this class date:

// date.cpp

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

//numero di giorni per ogni mese
const int Date::days[] = { 0, 31, 28, 31, 30, 31, 30,
31, 31, 30, 31, 30, 31 };

//costruttore
Date::Date( int m, int d, int y ) { setDate( m, d, y ); }

//set del giorno con controlli
void Date::setDay(int dd)
{

giornoCheck=1;

if ( month == 2 && leapYear( year ) )
{ if ( dd >= 1 && dd <= 29 ) day=dd;

else { day=1; giornoCheck=0;}
}

else
{ if ( dd >= 1 && dd <= days[ month ] ) day=dd;

else {day=1; giornoCheck=0;}

}
}

//set del mese con controlli
void Date::setMonth(int mm)
{
meseCheck=1;

if ( mm >= 1 && mm <= 12 ) month= mm;
else {month= 1; meseCheck=0; }

}

//set dell'anno con controlli
void Date::setYear(int yy)
{
annoCheck=1;

if ( yy >= 1900 && yy <= 2100) year = yy;
else {year = 2002; annoCheck=0; }
}

// Set della data
void Date::setDate( int mm, int dd, int yy )
{
setMonth(mm);
setYear(yy);
setDay(dd);

}

// le 3 get

int Date::getMonth() const {

return month;
}

int Date::getDay() const {

return day;
}

int Date::getYear() const {

return year;
}

//per usare l'operatore = anche con le date
bool Date::operator==(const Date & d) const {

return (d.month==month)&&(d.day==day)&&(d.year==year);

}

//per usare l'operatore < anche con le date
bool Date::operator<(const Date & d) const {

return (day+ ( month * days[month])+ (365*year) ) < ( d.day + (d.month * d.days[month]) + (365* d.year) );
}

//per usare l'operatore + anche con le date
Date Date::operator+( int g) const {

return Date( month , day+g , year );
}

//per usare l'operatore - anche con le date
Date Date::operator-( int g) const {

return Date( month , day-g , year );

}

//resoconto di validità totale
bool Date::isValid()
{

if ( giornoCheck==1 && annoCheck==1 && meseCheck==1) return true;

else return false;

}

//singoli resoconti di validità

bool Date::isDayValid()
{
return giornoCheck;
}

bool Date::isMonthValid()
{
return meseCheck;
}

bool Date::isYearValid()
{
return annoCheck;
}

// Operatore di Preincremento
Date & Date::operator++()
{
helpIncrement();
return *this;
}

// Operatore di postincremento

Date Date::operator++( int )
{
Date temp = *this;
helpIncrement();

// oggetto temporaneo salvato e non incrementato
return temp;
}

// aggiunge dei giorni ad una data
const Date &Date::operator+=( int additionalDays )
{
for ( int i = 0; i < additionalDays; i++ )
helpIncrement();

return *this;
}

//Controllo se bisestile o no

bool Date::leapYear( int y ) const
{
if ( y % 400 == 0 || ( y % 100 != 0 && y % 4 == 0 ) )
return true; // bisestile
else
return false; // non bisestile
}

//controlla che il giorno sia compatibile col mese
bool Date::endOfMonth( int d ) const
{
if ( month == 2 && leapYear( year ) )
return d == 29; // per febbraio
else
return d == days[ month ];
}

//incrementa la data
void Date::helpIncrement()
{
if ( endOfMonth( day ) && month == 12 ) { // finito l'anno
day = 1;
month = 1;
++year;
}
else if ( endOfMonth( day ) ) { // finito il mese
day = 1;
++month;
}
else // tutto ok si può incrementare
++day;
}

// per la stampa, overload dell'operatore <<
ostream &operator<<( ostream &output, const Date &d )
{
static char *monthName[ 13 ] = { "", "Gennaio",
"Febbraio", "Marzo", "Aprile", "Maggio", "Giugno",
"Luglio", "Agosto", "Settembre", "Ottobre",
"Novembre", "Dicembre" };

output << d.getDay() << ' '
<< monthName[ d.getMonth() ] << ' '<<d.getYear();

return output; //operatore a cascata
}

//per l'acquisizione, overload dell'operator >>
istream &operator>>( istream &input, Date &d )
{

int aux;

input >> aux;
d.setDay(aux);
input.ignore();
input >> aux;
d.setMonth(aux);
input.ignore();
input >> aux;
d.setYear(aux);

return input;

}

//legge la data del pc
Date Date::today()
{
time_t tempo_cal( time(NULL) );
struct tm * tempo_oggi ( localtime(&tempo_cal) );

return Date( tempo_oggi->tm_mon +1, tempo_oggi->tm_mday,tempo_oggi->tm_year +1900 );
}

please give an example of using the operator>> to insert the date

Member_2_1001466

operator+ and operator- don't check whether there is an overflow from the day to another month or year.
For the operator>> you should look at what will be in the stream when it was written with operator<<. The month is not an int any more.

Was that your question?

giggiaus

ASKER

I want only an example on how to use operator>> (of class date) to fill in the code.

Member_2_1001466

ifstream is ("yourfile.txt"); // has to be intialized
Date d;

is >> d;

giggiaus

ASKER

I have insert your exaple adepted to my code but it give me this error on compilation:

paerse error before '>'
on line is>>d

Member_2_1001466

The following headers <iostream> and <fstream> need to be included. A parse error could be due to an error on the line before like ommiting the ; at the end of a command. Can you show the code of the example?

itsmeandnobodyelse

I could give you an example of a class that is a little bit simpler:

class Date
{
public:
string date;
};

istream& operator>>(istream& is, Date& dt)
{
is >> dt.date;
return is;
}

int main()
{
Date dt;
cin >> dt;
cout << dt.date << endl;
return 0;
}

Note, that operator>> function is defined outside of class.

You could easily adapt your class if you provide an operator=() that takes a const string& as argument
istream& operator>>(istream& is, Date& dt)
{
string temp;
is >> temp;
dt = temp; // Here the operator= applies
return is;
}

Tell me, if you need more help.

Regards, Alex

giggiaus

ASKER

hi Alex,
how can I use the overloaded operartor>> of my class Date in my code

itsmeandnobodyelse

You see it in

int main()
{
// You would need a default constructor setting all members to 0 (invalid date)
Date dt; // or use your constructor: Date dt(0, 0, 0);

// Print to screen:
cout << "Please type in a valid date (DD.MM.YYYY): " << endl;

// Then you may type in the date from keyboard as string, e. g. "10.12.2003"
cin >> dt;

// This code is only for test
cout << dt.day << "." << dt.month << "." << dt.year << endl;
return 0;
}

Hope, that helps

Alex

giggiaus

ASKER

the compiler give me this error:

parse error before ">" in cin >> dt; .....................

Member_2_1001466

Does the error go away when you replace cin with std::cin?
In that case you could add the line
using namespace std;
just after the include lines.

What compiler are you using? Could be easier to follow if one test it on the same one.

itsmeandnobodyelse

That could have two reasons:

1. You forgot to include the iostream header

#include <iostream>

2. You forgot to include namespace std

using namespace std;

That statement you may include in Date.h after all standard includes:

// date.h
#ifndef DATE_H
#define DATE_H

#include <string>
#include <iostream>
...

using namespace std;

...

class Date
{
...
};

#endif

giggiaus

ASKER

the error there is again.....

itsmeandnobodyelse

Can you try

std::cin >> dt;

as STeH has suggested?

If this compiles you should include the line

using namespace std;

directly before

int main()
{
...
cin >> dt;
...
}

If the error still exists you should check the line before if the semicolon ';' is present and nothing is between
semicolon and cin.

Regards, Alex

giggiaus

ASKER

my compilator is devcpp 4.9.6.0

giggiaus

ASKER

and now the error is :
parse error before "::" in line std::cin>>dt;

my code is :
.......
do
cout<<"insert the date(DD.MM.YYYY)";
std::cin>>dt;
while (dt.isValid());
.................

itsmeandnobodyelse

Add some scope brackets

do
{
cout<<"insert the date(DD.MM.YYYY)";
std::cin>>dt;
}
while (dt.isValid());

regards, Alex

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Member_2_1001466

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giggiaus

ASKER

Thank you SteH, I solved the prblem....but now i have another problem
see the question: "(difference between two date) to number of days"