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Calender issues

urrutiaeric (2)
So i am creating a calendar in c++ for school and ive got the code down for the most part but when it tries to output a calendar for December 1753 it comes out completely wrong.

the calendar starts January 1753 and goes from there

here is my code:

#include <iostream>
#include<iomanip>
using namespace std;


int numDays = 0;
int offset = 0 ;

int getMonth()
{
int month = 0;
do
{
cout << "Enter a month number: ";
cin >> month;

if (month < 1 || month > 12)
cout << "Month must be between 1 and 12.\n";
}
while (month < 1 || month > 12);


return month;
}

int getYear()
{
int year = 0;
do
{
cout << "Enter year: ";
cin >> year;

if (year < 1753)
cout << "Year must be 1753 or later.\n";
}
while (year < 1753);

return year;
}

bool isLeapYear(int year)
{
bool leapYear = false;

if (year % 4 == 0)
leapYear = true;
if (year % 100 == 0 && year % 400 != 0)
leapYear = false;

return leapYear;
}

int calcNumDays(int month, int year)
{
int numDays;

if (month == 1)
numDays = 31;
else if (month == 2)
{
if (isLeapYear(year))
numDays = 29;
else
numDays = 28;
}
else if (month == 3)
numDays = 31;
else if (month == 4)
numDays = 30;
else if (month == 5)
numDays = 31;
else if (month == 6)
numDays = 30;
else if (month == 7)
numDays = 31;
else if (month == 8)
numDays = 31;
else if (month == 9)
numDays = 30;
else if (month == 10)
numDays = 31;
else if (month == 11)
numDays = 30;
else if (month == 12)
numDays = 31;

return numDays;
}

int getOffset(int month, int year)
{
int sum = 0;

for (int yearCount = 1753; yearCount < year; yearCount++)
{
if (isLeapYear(yearCount))
sum += 366;
else
sum += 365;
}
for (int monthCount = 1; monthCount < month; monthCount++)
{
sum += calcNumDays(monthCount, month);
}

int offset = sum % 7;

return offset;
}

void displayHeader(int month, int year)
{
switch (month)
{
case 1:
cout << endl << "January, " << year << endl;
break;
case 2:
cout << endl << "February, " << year << endl;
break;
case 3:
cout << endl << "March, " << year << endl;
break;
case 4:
cout << endl << "April, " << year << endl;
break;
case 5:
cout << endl << "May, " << year << endl;
break;
case 6:
cout << endl << "June, " << year << endl;
break;
case 7:
cout << endl << "July, " << year << endl;
break;
case 8:
cout << endl << "August, " << year << endl;
break;
case 9:
cout << endl << "September, " << year << endl;
break;
case 10:
cout << endl << "October, " << year << endl;
break;
case 11:
cout << endl << "November, " << year << endl;
break;
case 12:
cout << endl << "December, " << year << endl;
break;
}
return;
}

void displayTable(int offset, int numDays)
{
cout << setw(4) << "Su"
<< setw(4) << "Mo"
<< setw(4) << "Tu"
<< setw(4) << "We"
<< setw(4) << "Th"
<< setw(4) << "Fr"
<< setw(4) << "Sa"
<< endl;

if (offset != 6)
{
for(int spaceCount = 0; spaceCount <= offset; spaceCount++)
{
cout << " ";
}
}
for(int dayCount = 1; dayCount <= numDays; dayCount++)
{
cout << setw(4) << dayCount;

if ((dayCount + offset + 1) % 7 == 0 && dayCount + 1 <= numDays)
cout << endl;
}
cout << endl;

return;
}




int main()
{
int month = getMonth();
int year = getYear();
int numDays = calcNumDays(month, year);
int offset = getOffset(month, year);

displayHeader(month, year);
displayTable(offset, numDays);
}

Here is the out put for December 1753 with what it actually needs to say included:

December, 1753
> Su Mo Tu We Th Fr Sa
> 1 2 3 4 5 6 7\n
Exp: 1\n
> 8 9 10 11 12 13 14\n
Exp: 2 3 4 5 6 7 8\n
> 15 16 17 18 19 20 21\n
Exp: 9 10 11 12 13 14 15\n
> 22 23 24 25 26 27 28\n
Exp: 16 17 18 19 20 21 22\n
> 29 30 31\n
Exp: 23 24 25 26 27 28 29\n
>
Exp: 30 31\n

Last edited on
ne555 (10692)
> void displayTable(int offset, int numDays)
explain what's the offset, what does it represent, and which values may it take.
whitenite1 (1785)
@urrutiaeric

Made a few minor changes to your code, but the days fall in their correct weekdays, now.

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// Calendar Issues.cpp : main project file.

#include <iostream>
#include <iomanip>

using namespace std;


int numDays = 0;
int offset = 0 ;

int getMonth()
{
	int month = 0;
	do
	{
		cout << "Enter a month number: ";
		cin >> month;

		if (month < 1 || month > 12)
			cout << "Month must be between 1 and 12.\n";
	}
	while (month < 1 || month > 12);

	return month;
}

int getYear()
{
	int year = 0;
	do
	{
		cout << "Enter year: ";
		cin >> year;

		if (year < 1753)
			cout << "Year must be 1753 or later.\n";
	} while (year < 1753);

	return year;
}

bool isLeapYear(int year)
{
	bool leapYear = false;

	if (year % 4 == 0)
		leapYear = true;
	if (year % 100 == 0 && year % 400 != 0)
		leapYear = false;

	return leapYear;
}

int calcNumDays(int month, int year)
{
	int numDays;

	if (month == 1)
		numDays = 31;
	else if (month == 2)
	{
		if (isLeapYear(year))
			numDays = 29;
		else
			numDays = 28;
	}
	else if (month == 3)
		numDays = 31;
	else if (month == 4)
		numDays = 30;
	else if (month == 5)
		numDays = 31;
	else if (month == 6)
		numDays = 30;
	else if (month == 7)
		numDays = 31;
	else if (month == 8)
		numDays = 31;
	else if (month == 9)
		numDays = 30;
	else if (month == 10)
		numDays = 31;
	else if (month == 11)
		numDays = 30;
	else if (month == 12)
		numDays = 31;

	return numDays;
}

int getOffset(int month, int year)
{
	// Revised getOffset function
	int t[12] = { 0, 3, 2, 5, 0, 3, 5, 1, 4, 6, 2, 4 };
	int offset = year - ((month-1) < 2);
	offset = (offset + offset / 4 - offset / 100 + offset / 400 + t[month-1] + 1) % 7;
	// offset = 0 for Sunday, 1 for Monday.. etc.
	return offset;
}

void displayHeader(int month, int year)
{
	switch (month)
	{
	case 1:
		cout << endl << "January, " << year << endl;
		break;
	case 2:
		cout << endl << "February, " << year << endl;
		break;
	case 3:
		cout << endl << "March, " << year << endl;
		break;
	case 4:
		cout << endl << "April, " << year << endl;
		break;
	case 5:
		cout << endl << "May, " << year << endl;
		break;
	case 6:
		cout << endl << "June, " << year << endl;
		break;
	case 7:
		cout << endl << "July, " << year << endl;
		break;
	case 8:
		cout << endl << "August, " << year << endl;
		break;
	case 9:
		cout << endl << "September, " << year << endl;
		break;
	case 10:
		cout << endl << "October, " << year << endl;
		break;
	case 11:
		cout << endl << "November, " << year << endl;
		break;
	case 12:
		cout << endl << "December, " << year << endl;
		break;
	}
	return;
}

void displayTable(int offset, int numDays)
{
	cout << setw(4) << "Su"
		<< setw(4) << "Mo"
		<< setw(4) << "Tu"
		<< setw(4) << "We"
		<< setw(4) << "Th"
		<< setw(4) << "Fr"
		<< setw(4) << "Sa"
		<< endl;

	cout << setw(4) << "";// Setting starting number below Sunday
	for(int spaceCount = 1; spaceCount < offset; spaceCount++)
	{
		cout << setw(4) << " ";// Move spacing over for each offset 
	}

	for(int dayCount = 1; dayCount <= numDays; dayCount++)
	{
		cout << setw(4) << dayCount;

		if ((dayCount + offset) % 7 == 0) // Don't need the '+1' or if dayCount > numDays,
			//since loop CAN'T go beyond numDays 
				cout << endl;
	}
	cout << endl;

	return;
}

int main()
{
	int month = getMonth();
	int year = getYear();
	int numDays = calcNumDays(month, year);
	int offset = getOffset(month, year);

	displayHeader(month, year);
	displayTable(offset, numDays);
}
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