#ifndef RNAFUNCTIONS
#define RNAFUNCTIONS

//declaration
void fx();

#endif

#include <iostream>
#include "RMAfunctions.h"
using namespace std;

//definition
void fx(){
    cout<<"hello Word"<<endl;
}

#include <windows.h>
    #include <fstream>
    #include <string>
    #include <iostream>
        #include "RMAfunctions.h"
        using namespace std;

//I have tried calling fx() here

    LRESULT CALLBACK WndProc(HWND hwnd, UINT Message, WPARAM wParam, LPARAM lParam) {
//I have tried calling fx() here
}

    int WINAPI WinMain(HINSTANCE hInstance, HINSTANCE hPrevInstance, LPSTR lpCmdLine, int nCmdShow) {
//I have tried calling fx() here
}