(20 points) Complete the code for the day_of_week function in Chrono.cpp and wri
ID: 3565295 • Letter: #
Question
(20 points) Complete the code for the day_of_week function in Chrono.cpp and write hw6pr1.cpp to repeatedly ask for a date and print out the day of the week,
like this:
Date (year, month, day)? (2014,10,21)
That is a Tuesday.
Date (year, month, day)? (2000,3,1)
That is a Wednesday.
Date (year, month, day)? (1900,3,1)
That is a Thursday.
Hints: Look up Zeller's Congruence. Be careful about encoding Sunday as a 0 or a 1. Be careful about int divided by int. Don't forget to code the leapyear function correctly.
#include "Chrono.h"
namespace Chrono {
// member function definitions:
//------------------------------------------------------------------------------
Date::Date(int yy, Month mm, int dd)
: y(yy), m(mm), d(dd)
{
if (!is_date(yy,mm,dd)) throw Invalid();
}
//------------------------------------------------------------------------------
const Date& default_date()
{
static const Date dd(2001,Date::jan,1); // start of 21st century
return dd;
}
//------------------------------------------------------------------------------
Date::Date()
:y(default_date().year()),
m(default_date().month()),
d(default_date().day())
{
}
//------------------------------------------------------------------------------
void Date:: add_day(int n)
{
d++;
// add date
}
//------------------------------------------------------------------------------
void Date::add_month(int n)
{
int temp = int(m);
temp++;
m = Month(temp);
//add month
}
//------------------------------------------------------------------------------
void Date::add_year(int n)
{
if (m==feb && d==29 && !leapyear(y+n)) { // beware of leap years!
m = mar; // use March 1 instead of February 29
d = 1;
}
y+=n;
}
//------------------------------------------------------------------------------
// helper functions:
bool is_date(int y, Date::Month m, int d)
{
// assume that y is valid
if (d<=0) return false; // d must be positive
int days_in_month = 31; // most months have 31 days
switch (m) {
case Date::feb: // the length of February varies
days_in_month = (leapyear(y))?29:28;
break;
case Date::apr: case Date::jun: case Date::sep: case Date::nov:
days_in_month = 30; // the rest have 30 days
break;
}
if (days_in_month<d) return false;
return true;
}
//------------------------------------------------------------------------------
bool leapyear(int y)
{
// See exercise ???
return false;
}
//------------------------------------------------------------------------------
bool operator==(const Date& a, const Date& b)
{
return a.year()==b.year()
&& a.month()==b.month()
&& a.day()==b.day();
}
//------------------------------------------------------------------------------
bool operator!=(const Date& a, const Date& b)
{
return !(a==b);
}
//------------------------------------------------------------------------------
ostream& operator<<(ostream& os, const Date& d)
{
return os << '(' << d.year()
<< ',' << d.month()
<< ',' << d.day()
<< ')';
}
//------------------------------------------------------------------------------
istream& operator>>(istream& is, Date& dd)
{
int y, m, d;
char ch1, ch2, ch3, ch4;
is >> ch1 >> y >> ch2 >> m >> ch3 >> d >> ch4;
if (!is) return is;
if (ch1!='(' || ch2!=',' || ch3!=',' || ch4!=')') { // oops: format error
is.clear(ios_base::failbit); // set the fail bit
return is;
}
dd = Date(y,Date::Month(m),d); // update dd
return is;
}
//------------------------------------------------------------------------------
enum Day {
sunday, monday, tuesday, wednesday, thursday, friday, saturday
};
//------------------------------------------------------------------------------
Day day_of_week(const Date& d)
{
// ...
return sunday;
}
//------------------------------------------------------------------------------
Date next_Sunday(const Date& d)
{
// ...
return d;
}
//------------------------------------------------------------------------------
Date next_weekday(const Date& d)
{
// ...
return d;
}
Date& Date::operator++()
{
add_day(1);
if (is_date(year(),month(),day())==false)
{
d=1;
if (month()==Date::Month::dec)
{
m=Date::Month::jan;
add_year(1);
}
else
{
add_month(1);
}
return *this;
//d=1;
}
}
//------------------------------------------------------------------------------
} // Chrono
// file Chrono.h
namespace Chrono {
//------------------------------------------------------------------------------
class Date {
public:
enum Month {
jan=1, feb, mar, apr, may, jun, jul, aug, sep, oct, nov, dec
};
class Invalid { }; // to throw as exception
Date(int y, Month m, int d); // check for valid date and initialize
Date(); // default constructor
// the default copy operations are fine
// non-modifying operations:
int day() const { return d; }
Month month() const { return m; }
int year() const { return y; }
// modifying operations:
void add_day(int n);
void add_month(int n);
void add_year(int n);
Date& operator++();
private:
int y;
Month m;
int d;
};
bool is_date(int y, Date::Month m, int d); // true for valid date
bool leapyear(int y); // true if y is a leap year
bool operator==(const Date& a, const Date& b);
bool operator!=(const Date& a, const Date& b);
ostream& operator<<(ostream& os, const Date& d);
istream& operator>>(istream& is, Date& dd);
const Date& default_date();
} // Chrono
#endif
.
Explanation / Answer
#include using namespace std; // file Chrono.h namespace Chrono { //------------------------------------------------------------------------------ class Date { public: enum Month { jan=1, feb, mar, apr, may, jun, jul, aug, sep, oct, nov, dec }; class Invalid { }; // to throw as exception Date(int y, Month m, int d); // check for valid date and initialize Date(); // default constructor // the default copy operations are fine // non-modifying operations: int day() const { return d; } Month month() const { return m; } int year() const { return y; } // modifying operations: void add_day(int n); void add_month(int n); void add_year(int n); private: int y; Month m; int d; }; bool is_date(int y, Date::Month m, int d); // true for valid date bool leapyear(int y); // true if y is a leap year bool operator==(const Date& a, const Date& b); bool operator!=(const Date& a, const Date& b); ostream& operator(istream& is, Date& dd); const Date& default_date(); } // Chrono //------------------------------------------------------------------------------ //The definitions go into Chrono.cpp: // Chrono.cpp namespace Chrono { // member function definitions: Date::Date(int yy, Month mm, int dd) : y(yy), m(mm), d(dd) { if (!is_date(yy,mm,dd)) throw Invalid(); } const Date& default_date(); Date::Date() :y(default_date().year()), m(default_date().month()), d(default_date().day()) { } int days_in_month(int y, Date::Month m); void Date::add_day(int n) { // use linear_day() below or things get really messy if (nRelated Questions
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