I am using the 3 files of code from the C++ book Chapter 11 and 11.8 Case Study:A Date Class with both cpp files and header file my questoion is how do i (add overloaded operator for "--" (pre and post), "-=", and ">>".
For ">>", user expected to type in the format of "mm/dd/yyyy".) Here is the code:
Richard_10 0 Newbie Poster
Richard_10 0 Newbie Poster
h file
#ifndef DATE_H
#define DATE_H
#include <iostream>
using namespace std;
{
class Date
friend ostream &operator<<( ostream &, const Date & );
// friend Rational operator--(Rational &);
public:
Date( int m = 1, int d = 1, int y = 1900 ); // default constructor
void setDate( int, int, int ); // set month, day, year
Date &operator++(); // prefix increment operator
Date operator++( int ); // postfix increment operator
const Date &operator+=( int ); // add days, modify object
static bool leapYear( int ); // is date in a leap year?
bool endOfMonth( int ) const; // is date at the end of month?
private:
//int numerator;
//int denominator;
int month;
int day;
int year;
static const int days[]; // array of days per month
void helpIncrement(); // utility function for incrementing date
}; // end class Date
#endif
date.cpp
#include <iostream>
#include <string>
#include "Date.h"
using namespace std;
// initialize static member; one classwide copy
const int Date::days[] =
{ 0, 31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31 };
// Date constructor
Date::Date( int month, int day, int year )
{
setDate( month, day, year );
} // end Date constructor
// set month, day and year
void Date::setDate( int mm, int dd, int yy )
{
if ( mm >= 1 && mm <= 12 )
month = mm;
else
throw invalid_argument( "Month must be 1-12" );
if ( yy >= 1900 && yy <= 2100 )
year = yy;
else
throw invalid_argument( "Year must be >= 1900 and <= 2100" );
// test for a leap year
if ( ( month == 2 && leapYear( year ) && dd >= 1 && dd <= 29 ) ||
( dd >= 1 && dd <= days[ month ] ) )
day = dd;
else
throw invalid_argument(
"Day is out of range for current month and year" );
} // end function setDate
// overloaded prefix increment operator
Date &Date::operator++()
{
helpIncrement(); // increment date
return *this; // reference return to create an lvalue
} // end function operator++
// overloaded postfix increment operator; note that the
// dummy integer parameter does not have a parameter name
Date Date::operator++( int )
{
Date temp = *this; // hold current state of object
helpIncrement();
// return unincremented, saved, temporary object
return temp; // value return; not a reference return
} // end function operator++
// add specified number of days to date
const Date &Date::operator+=( int additionalDays )
{
for ( int i = 0; i < additionalDays; ++i )
helpIncrement();
return *this; // enables cascading
} // end function operator+=
// if the year is a leap year, return true; otherwise, return false
bool Date::leapYear( int testYear )
{
if ( testYear % 400 == 0 ||
( testYear % 100 != 0 && testYear % 4 == 0 ) )
return true; // a leap year
else
return false; // not a leap year
} // end function leapYear
// determine whether the day is the last day of the month
bool Date::endOfMonth( int testDay ) const
{
if ( month == 2 && leapYear( year ) )
return testDay == 29; // last day of Feb. in leap year
else
return testDay == days[ month ];
} // end function endOfMonth
// function to help increment the date
void Date::helpIncrement()
{
// day is not end of month
if ( !endOfMonth( day ) )
++day; // increment day
else
if ( month < 12 ) // day is end of month and month < 12
{
++month; // increment month
day = 1; // first day of new month
} // end if
else // last day of year
{
++year; // increment year
month = 1; // first month of new year
day = 1; // first day of new month
} // end else
} // end function helpIncrement
// overloaded output operator
ostream &operator<<( ostream &output, const Date &d )
{
static string monthName[ 13 ] = { "", "January", "February",
"March", "April", "May", "June", "July", "August",
"September", "October", "November", "December" };
output << monthName[ d.month ] << ' ' << d.day << ", " << d.year;
return output; // enables cascading
} // end function operator<<
& the main cpp project file:
#include <iostream>
#include "Date.h" // Date class definition
using namespace std;
int main()
{
Date d1( 12, 27, 2010 ); // December 27, 2010
Date d2; // defaults to January 1, 1900
cout << "d1 is " << d1 << "nd2 is " << d2;
cout << "nnd1 += 7 is " << ( d1 += 7 );
d2.setDate( 2, 28, 2008 );
cout << "nn d2 is " << d2;
cout << "n++d2 is " << ++d2 << " (leap year allows 29th)";
Date d3( 7, 13, 2010 );
cout << "nnTesting the prefix increment operator:n"
<< " d3 is " << d3 << endl;
cout << "++d3 is " << ++d3 << endl;
cout << " d3 is " << d3;
cout << "nnTesting the postfix increment operator:n"
<< " d3 is " << d3 << endl;
cout << "d3++ is " << d3++ << endl;
cout << " d3 is " << d3 << endl;
} // end main
Richard_10 0 Newbie Poster
Those are the 3 files that I am working on how do i add ther overloaded operator for "--" (pre and post), "-=", and ">>"?
Ancient Dragon 5,243 Achieved Level 70 Team Colleague Featured Poster
what is "--" ? do you mean "+=" since you also specified "-="?
Richard_10 0 Newbie Poster
That's something the professor had said to add im not sure cause i don't see anything with "--"
Ancient Dragon 5,243 Achieved Level 70 Team Colleague Featured Poster
There is no such operator as "--". You probably misundertood your instructor, he/she probably meant "==", which is the text to see if both sides of the operator are identical (called the equal operator).
The code you posted already contains examples of operator overloading, just follow those examples to create the new operators.
mike_2000_17 2,669 21st Century Viking Team Colleague Featured Poster
The operator -- is just the decrement operator, i.e., the opposite of ++.
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