Using header files correctly - c++

Question

I'm trying to expand my C++ game hacking skills as when I was starting (2 years ago) I made a bad decision: continue in game hacking with vb.net instead of learning c++ (as I had some vb.net knowledge and 0 knowledge with other languages)
So, now as the very first steps I have to create my toolkit, where I will be using my own templates:
Nathalib.h (my template with all common functions for game hacking).
#pragma once
#include <iostream>
#include <Windows.h>
#include <string>
#include <TlHelp32.h>
#include <stdio.h>
using namespace std;
DWORD ProcessID;
int FindProcessByName(string name)
{
HWND hwnd = FindWindowA(0, name);
GetWindowThreadProcessId(hwnd, &ProcessID);
if (hwnd)
{
return ProcessID;
}
else
{
return 0;
}
}
Hack.cpp (obviously the cheat, will be different for every game).
#pragma once
#include "pch.h"
#include <iostream>
#include <Windows.h>
#include <string>
#include <Nathalib.h>
using namespace std;
int main()
{
While(True)
{
cout << FindProcessByName("Calculator") << endl;
getchar();
cout << "-----------------------------------" << endl << endl;
}
return 0;
}
Target.cpp (as we're not bad boys, I must provide my own target).
#include "pch.h"
#include <iostream>
#include <Windows.h>
#include <string>
using namespace std;
#define CHAR_ARRAY_SIZE 128
int main()
{
int varInt = 123456;
string varString = "DefaultString";
char arrChar[CHAR_ARRAY_SIZE] = "Long char array right there ->";
int * ptr2int;
ptr2int = &varInt;
int ** ptr2ptr;
ptr2ptr = &ptr2int;
int *** ptr2ptr2;
ptr2ptr2 = &ptr2ptr;
while(True) {
cout << "Process ID: " << GetCurrentProcessId() << endl;
cout << "varInt (0x" << &varInt << ") = " << varInt << endl;
cout << "varString (0x" << &varString << ") = " << varString << endl;
cout << "varChar (0x" << &arrChar << ") = " << arrChar << endl;
cout << "ptr2int (0x" << hex << &ptr2int << ") = " << ptr2int << endl;
cout << "ptr2ptr (0x" << hex << &ptr2ptr << ") = " << ptr2ptr << endl;
cout << "ptr2ptr2 (0x" << hex << &ptr2ptr2 << ") = " << ptr2ptr2 << endl;
cout << "Press ENTER to print again." << endl;
getchar();
cout << "-----------------------------------" << endl << endl;
}
return 0;
}
I don't know why the header file is not being recognized.
This is the correct way to include header files? Should I create a namespace/class/object for calling it?
It's the correct way creating a header file? Or I should create another kind of project/resource for this purpose?
How should I call my library methods? Like LibraryName.MethodName?
I just come from other languages and some ideas/features are not available in the other languages (that's why I'm interested in this one)
If there's something I forgot to add, please tell me and I will update
Thanks

Answer 1

There are multiple errors - please check your textbook.
You include your own headers with #include "". System headers are included with #include<>
The header file generally contains function declarations. Function bodies go into the corresponding .cpp file.
You call your library functions by their name. If they're in a namespace, that might mean the format is namespacename::functionname(arguments).

Answer 2

There are two ways to include headers, using "" or <>
with <> the file will be searched in the system search path (which is not the $PATH variabel, but the list of paths provided with `-I' together with standard headers already known by compiler) and included if found
with "" the file will be search in the current folder and in the system search path
Assuming your header is in th esame folder of hack.cpp, you should use
#include "Nathalib.h"

Answer 3

First off, your header lacks include guards, #pragma once only works with msvc++.
Your header file is probably not in PATH, so you need to specify it's path relative to your project. If your header file is in the same root as your cpp file, all you need to do is change the include statement for that header file to #include "Nathalib.h" otherwise you'll have to specify the relative path.

Answer 4

To add to other aswers- why you should put declaration of function in .h file, while its definition to .cpp file: Writing function definition in header files in C++
I suggest to find some c++ tutorials for example: http://www.tutorialspoint.com/cplusplus/cpp_functions.htm
You should learn tutorials first, making some exercises on simply code. Personally I prefer check then most simply code for new programming construct. Then more complicated.
After such learning you may use for reference also : http://www.cplusplus.com and https://en.cppreference.com/w/