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Enter the year, then print the calendar

I am fixated on the following problem from my C programming class:

Write a program in which the user enters a year and then displays a calendar (for the whole year).

I have no idea how to approach this problem. Usually I can start homework (this is an optional problem), but I'm really lost. We worked in chapters 1-10 of Deitel and Deitel (loops, arrays, pointers, I / O, etc.), but I don’t know how to approach this at all. Any hints or suggestions would be appreciated.

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This can help you understand the math of the calendar. If the fabulous book Calendar Calculations is not included in your university library, they can get you a reprint of an article by the same authors in Software and Practice. And ask your professor to request a book for the library.

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In general, when you have a big problem like this, you want to break it down into small problems that are easier to solve.

One small problem may arise here: if you know how many days a month, and on what weekday the first month comes, can you display a calendar for this month?

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char command[]="cal 2010";
sprintf(command,"cal %d",argv[1]);
system(command);

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Pseudo-Code, (YYYY-MM-DD):

void print_cal( int year ) {
    static char weekdays[] = { "Sun", "Mon", "Tue", "Wed", "Thu", "Fri", "Sat" };
    struct tm tm;
    for( int day=0; day<365; ++day ) {
        memset( &tm, 0, sizeof(tm) );
        tm.tm_year = year - 1900;
        tm.tm_mday = day;
        mktime( &tm ); // modifies tm

        printf( "%04d-%02d-%02d, %s\n", tm.tm_year, tm.tm_mon+1, tm.tm_mday, weekdays[tm.tm_wday] );
    }
}

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