Q: What's the difference between #include <> and #include "" ?
A: The <> syntax is typically used with Standard or system-supplied headers, while "" is typically used for a program's own header files. See also question 10.8b.
Additional links:
nice explanation
by Kaz Kylheku
An
article
and a longer
followup
I posted in 1997 exploring some of the finer points which
sometimes arise in deciding between #include ""and #include <>.
(Warning:
among the possibilities explored
is that of using #include <> for your own header files
under certain circumstances,
a practice which is not standard
and is not condoned by the readership of comp.lang.c.)