Question

Possible Duplicates:
[C] Header per source file.
In C++ why have header files and cpp files?
C++ – What should go into an .h file?

Is the only reason header files exist in C
so a developer can quickly see what functions are available
and what arguments they can take?

Or is it something to do with the compiler?

Why has no other language used this method?

Is it just me, or does it seem that having 2 sets of function definitions
will only lead to more maintenance and more room for errors?

Or is knowing about header files just something every C developer must know?

Answer 1

Header files are needed to declare functions and variables that are available. You might not have access to the definitions (=the .c files) at all; C supports binary-only distribution of code in libraries.