Ways to organize interface and implementation in C++
- by Felix Dombek
I've seen that there are several different paradigms in C++ concerning what goes into the header file and what to the cpp file. AFAIK, most people, especially those from a C background, do:
foo.h
class foo {
private:
int mem;
int bar();
public:
foo();
foo(const foo&);
foo& operator=(foo);
~foo();
}
foo.cpp
#include foo.h
foo::bar() { return mem; }
foo::foo() { mem = 42; }
foo::foo(const foo& f) { mem = f.mem; }
foo::operator=(foo f) { mem = f.mem; }
foo::~foo() {}
int main(int argc, char *argv[]) { foo f; }
However, my lecturers usually teach C++ to beginners like this:
foo.h
class foo {
private:
int mem;
int bar() { return mem; }
public:
foo() { mem = 42; }
foo(const foo& f) { mem = f.mem; }
foo& operator=(foo f) { mem = f.mem; }
~foo() {}
}
foo.cpp
#include foo.h
int main(int argc, char* argv[]) { foo f; }
// other global helper functions, DLL exports, and whatnot
Originally coming from Java, I have also always stuck to this second way for several reasons, such as that I only have to change something in one place if the interface or method names change, that I like the different indentation of things in classes when I look at their implementation, and that I find names more readable as foo compared to foo::foo.
I want to collect pro's and con's for either way. Maybe there are even still other ways?
One disadvantage of my way is of course the need for occasional forward declarations.
