Making a Calendar in C++

[mezzoforte]

Any ideas of how I can have a calendar for all 12 months print for any year?
The user inputs the year and the day of the week for January 1st of that year. (Sunday = 0, Monday = 1, etc.)


Could someone provide a pseudocode or any suggestions?

[Pickle Gunner]

You could have a system like this:

enum Month{All = days, Of = days, the = days, Months = days}

Find Starting Point

Recursive For Loop
-Print
-Call Apon Self

If the Days in the Month enum is at the max given then Month = Next in the sequence

[mezzoforte]

I couldn't figure out how to do what you were talking about, lol. But I made progress:

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




int main()
{
int mdays[] = {31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31};
int DaysinWeek = 0;
int year;
int day;
int FirstDayOfMonth = 0;
int month = 1;



cout << "Calendar Program" << endl << endl;
cout << "Please enter the year: ";
cin >> year;
if (year < 0)
{cout << "The year must be greater than or equal to 0!" << endl;
return 0;}
cout << "Please enter the day of the week of January 1st." << endl;
cout << "Enter 0 for Sunday, 1 for Monday, ..., 6 for Saturday: ";
cin >> day;
if (day < 0 || day > 6)
{cout << "The day of January 1st must be between 0 and 6!" << endl;
return 0;}

cout << endl << endl;






// Print this year's calendar
for (int month = 0; month < 12; ++month) {
{
	
for (int i = 0; i < DaysinWeek; ++i)
{cout << setw(3) << " ";}


if (month == 0)
{cout << "January \n";}

if (month == 1)
{cout << "February \n";
 if (year % 400 == 0 || (year % 4 == 0 && year % 100 != 0))
mdays[1] = 29;}

if (month == 2)
{cout << "March \n";}

if (month == 3)
{cout << "April \n";}

if (month == 4)
{cout << "May \n";}

if (month ==5)
{cout << "June \n";}

if (month == 6)
{cout << "July \n";}

if (month == 7)
{cout << "August \n";}

if (month == 8)
{cout << "September \n";}

if (month == 9)
{cout << "October \n";}

if (month == 10)
{cout << "November \n";}

if (month == 11)
{cout << "December \n";}

}


//spaces
for (int i = 0; i < day; i++)
	{cout << "  ";
}

  //Determine where the first day begins
day = 0;
    for (FirstDayOfMonth; FirstDayOfMonth < day; ++FirstDayOfMonth)
    {   
        cout << setw(3);
    } 

   






// Print this month's calendar
for (int mday = 0; mday < mdays[month]; ++mday) {
cout << setw(3) << mday + 1;
DaysinWeek++;
if (DaysinWeek == 7) {
cout << "\n" << setw(3);
DaysinWeek = 0;
}

}

// Set up for the next month
if (DaysinWeek != 7) {
cout << "\n";
}

cout << endl;
day = DaysinWeek + 1;
}



return 0;
}

This is what I get: http://i.imgur.com/9ypos.jpg
Can someone please tell me how to get the month names all aligned to the left? And how to fix the alignment of the first week?

[TheIdeasMan]

http://zanasi.chem.unisa.it/download/C.pdf

If you check this out, there is a C program that gives some clues about this.

One is to use 2 arrays, one for days in month, the other for month names. that makes it easier to look up the month name, without lots of if else clauses.

When I did this years ago, I remember there being a formula that calculated which day of the week it was given the day, month & year. It calculated the number of days since sometime in the 1700's (1752? a guess) , which was the last time that anyone meddled with the calendar. It wasn't a straight forward formula, our teachers gave it to us as part of the assignment.

I guess you could do the same thing, start from a date that you know which day it was, calc the number of days to the input date, use the % operator (modulus) to work out which day it is.

On my linux system, this is what I get for Jan 1800:

    January 1800    
Su Mo Tu We Th Fr Sa
          1  2  3  4
 5  6  7  8  9 10 11
12 13 14 15 16 17 18
19 20 21 22 23 24 25
26 27 28 29 30 31

    January 1900    
Su Mo Tu We Th Fr Sa
    1  2  3  4  5  6
 7  8  9 10 11 12 13
14 15 16 17 18 19 20
21 22 23 24 25 26 27
28 29 30 31

And Jan 2000:

    January 2000    
Su Mo Tu We Th Fr Sa
                   1
 2  3  4  5  6  7  8
 9 10 11 12 13 14 15
16 17 18 19 20 21 22
23 24 25 26 27 28 29
30 31

Your program will be better if it can handle a wide range of dates - you can use the jan 1900 & 2000 to see that your day of week calc works.

Hope all goes well