Converting month/day to day of year

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How can I convert month and day to the day of the year?

For example, converting FEBRUARY 1 to 32, with 32 meaning the 32nd day of the year.

There is a struct that needs to be a part of it. The struct could be something like this:

struct person {
  char name[30]
  char month;
  int day;
}

Posted 25-Mar-10 5:38am

Kurai90

Updated 25-Mar-10 8:43am

v3

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Luc Pattyn · Answer 1 · 2010-03-25T12:04:00

Solution 4

for January, day of year equals day of month;
for February, day of year equals day of month plus 31;
for all other months, you can't say without knowing the leap year situation.

:)

Posted 25-Mar-10 12:04pm

Luc Pattyn

Richard MacCutchan · Answer 2 · 2010-03-25T06:12:00

Solution 2

Take a look at the Time Management[^] functions in C. The struct tm type has a property containing the day of the year, so you just need to use the other functions to convert from a string to a date.

Posted 25-Mar-10 6:12am

Richard MacCutchan

William Winner · Answer 3 · 2010-03-25T12:49:00

What you're talking about is converting a Gregorian date to a Julian date.

See: Converting Between Julian Dates and Gregorian Calendar Dates [^]. You can write the equation in C, and then if you want the day of the year, just subtract the julian date of the day in question from the julian date from the 1st of January of the year.

The Manoj Kumar · Answer 4 · 2010-03-25T07:53:00

Solution 3

Try out this link (nice explanation and formulae):
http://www.codecogs.com/d-ox/units/date/dayofyear.php[^]

Posted 25-Mar-10 7:53am

The Manoj Kumar

**PSK_** · Answer 5 · 2010-03-25T05:53:00

Check this, you can use the logic.

http://www.dotnetspider.com/resources/21013-C-function-will-determine-day-number-within.aspx[^]

added, LP:

That link points to C# code and relies on the DateTime class in .NET, that is not very relevant to the question which specified C. The code also is horrible as it converts a DateTime to a string, later on parses it again to a DateTime, etc.

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