Should every C or C++ file have an associated header file?

Question

Should every .C or .cpp file should have a header (.h) file for it?

Suppose there are following C files :

1. Main.C

2. Func1.C

3. <

Answer 1

Bjarne Stroustrup Explains it beautifully in his book "The C++ Programming Language"....

The single header style of physical partitioning is most useful when the program is small and its parts are not intended for separate use. When namespaces are used, the logical structure of the program can still be explained in a single header file.

For larger Programs, the single header file approach is unworkable in a conventional file-based development environment. A change to the common header forces recompilation of the whole program, and updates of that single header by several programmers are error prone. Unless strong emphasis is placed on programming styles relying heavily on namespaces and classes, the logical structure deteriorates as program grows.

An alternative physical organization lets each logical module have its own header defining the facilities it provides. Each .c file then has a corresponding h. file specifying what it provides(its interface). Each .c module includes its own .h file and usually also other .h files that specifies what it needs from other modules in order to implement the services advertised in its interface. This physical organization corresponds to the logical organization of a module. The multiple header approach makes it easy to determine the dependencies. The single header approach forces us to look at every declarations used by any module and decide if its relevant. The simple fact is that maintenance of a code is invariably done with incomplete information and from a local perspective. The better localization leads to less information to compile a module and thus faster compilation..