struct tm - Why days start at 1 whereas months start at 0?

Asked May 25 '13 at 17:24

Active May 25 '13 at 17:24

Viewed 222 times

As you can see here in struct tm, days are 1 indexed while months are 0 indexed. The same can be seen in other languages like Java.

What is the reason of doing this ?

The only purpose I can find is to make easier things like this :

const char *names[] = { "January", "February", ... };
names[date.tm_mon];

asked May 25 '13 at 17:24

Raphael Javaux

Possible dup: http://stackoverflow.com/questions/344380/why-is-january-month-0-in-java-calendar – Ray Toal May 25 '13 at 17:26
@RayToal - not exactly, the other question only ask about the java implementation. – Andreas Dolk May 25 '13 at 17:28
I suspect the answer is "just because". – Alnitak May 25 '13 at 17:30
@Andreas_D: I suspect Java simply inherited this from C ... - I mean, as Java is OO .. ;-) – alk May 25 '13 at 17:30
But anyway, Jon's answer to the other (Java) question expands on C. http://stackoverflow.com/a/344400/105224 – Andreas Dolk May 25 '13 at 17:33
You may find an answer here: http://stackoverflow.com/questions/1453043/zero-based-month-numbering – PeterMmm May 25 '13 at 17:59

0 Answers0