Thread: user created header files

Correct! h. files just indicate what functions you can use. The .c/.cpp files have the real implentation. The erros that you got means that you do not have any implementation for the function that you used in your code.
When you put #include "file.cpp" you are telling to the compiler to add that file to the compilation process.
Later the "file.cpp", after compiled, will be linked with your code.

User defined headers are simple, you mention the header when you write the driver, but don't mention it when you compile. You mention the implementation when you compile, but don't mention it when you write the driver:

Code:

/* a.h */
void printa ( );

/* b.h */
void printb ( );

/* a.cpp */
#include <iostream>
#include "a.h"

void printa ( ) {
  std::cout<<"A"<<std::endl;
}

/* b.cpp */
#include <iostream>
#include "b.h"

void printb ( ) {
  std::cout<<"B"<<std::endl;
}

/* main.cpp */
#include "a.h"
#include "b.h"

int main ( ) {
  printa();
  printb();
}

/* Compile like so (your mileage may vary if you don't have GCC */
% gcc a.cpp b.cpp main.cpp
% ./a.out

You have header files that do all your declarations. Then you have implementation files for those header files that include the header files and define the declarations. Then your main program only has to include the header file, but you need to compile the implementation file and link it with the main program for everything to work.

Originally posted by twm
You have header files that do all your declarations. Then you have implementation files for those header files that include the header files and define the declarations. Then your main program only has to include the header file, but you need to compile the implementation file and link it with the main program for everything to work.

In other cases, you jut have the compiled code (a .o or .a file, for example). This happens when you download libraries of people that have their own reasons to "hide" the code.