Thread: Modules and Member Functions

I have 3 files: stack.h, calc,c and stack.c

Code:

void make_empty(void);
int is_empty(void);
int pop(void);

Code:

#include "stack.h"
main() {
     make_empty();
     ...
}

Code:

#include "stack.h"
int contents[100];
int top = 0;
//function definitions

I get that stack.h is the interface, calc.c is the client and that stack.c is the implementation of the module. My question is: What exactly is the module? The definition is "a collection of services", so I thought that would be stack.c, but it isn't?

Also if you can access data members of a structure using the . and -> operator, why can't you use it with objects and member functions?

Code:

struct blah{
    int a;
    int b;
};

blah *abc;
abc->a = 0;

Since -> means (*abc).a, why can't you use it when calling member functions outside the class?

Code:

class Fraction {
   int denom;
   int num;

public:
   void reduce();
};

Fraction *f1, *f2;
f1->reduce();