How to add other cpp files in the compilation command ?

See more:

C++

I have build a code and I have 2 cpp files. I did include in the header(.h) the functin and I add also add in the main cpp the "header.h", but one error comes with:

||=== Build: Debug in Ex2CppFILES (compiler: GNU GCC Compiler) ===|
obj\Debug\main.o||In function `Z7WndProcP6HWND__jjl@16':|
C:\Users\..............\main.cpp|14|undefined reference to `StaticWindow()'|
||error: ld returned 1 exit status|
||=== Build failed: 2 error(s), 0 warning(s) (0 minute(s), 0 second(s)) ===|

this is the code:

The main.cpp

//Headers
#include <windows.h>
#include "resources.h"

HWND hwnd;

LRESULT CALLBACK WndProc(HWND hwnd, UINT msg, WPARAM wp, LPARAM lp)
{
    switch(msg)
    {
    case WM_CREATE:
        {
            StaticWindow();
            break;
        }
    case WM_DESTROY:
        PostQuitMessage(0);
        break;
    default:
        return DefWindowProcW(hwnd, msg, wp, lp);
    }
    return 0;
}
int WINAPI WinMain(HINSTANCE hInst, HINSTANCE hPrevInst, LPSTR args, int nCmdShow)
{
    WNDCLASSW wc = {0};

    wc.hbrBackground = (HBRUSH)COLOR_WINDOW;
    wc.hCursor       = LoadCursor(NULL, IDC_ARROW);
    wc.hIcon         = LoadIcon(NULL, IDI_APPLICATION);
    wc.hInstance     = hInst;
    wc.lpfnWndProc   = WndProc;
    wc.lpszClassName = L"myWindowClass";

    if(!RegisterClassW(&wc))
        return -1;

    hwnd = CreateWindowW(L"myWindowClass", L"Ex2FilesC++", WS_OVERLAPPEDWINDOW,
                  350, 150, 700, 500, NULL, NULL, NULL, NULL);

    ShowWindow(hwnd, nCmdShow);
    UpdateWindow(hwnd);

    MSG msg = {0};

    while(GetMessage(&msg, NULL, 0, 0) > 0)
    {
        TranslateMessage(&msg);
        DispatchMessage(&msg);
    }
    return 0;
}

the resources.cpp

#include <windows.h>
#include "resources.h"

void StaticWindow(HWND hwnd)
{
    CreateWindowW(L"static", L"Static window from resources.cpp", WS_CHILD | WS_VISIBLE,
                  10, 20, 150, 50, hwnd, NULL, NULL, NULL);
}

resources.h

void StaticWindow();

What I have tried:

I'm using Code::Blocks ver 17.12
and C++ the language..

Please help. Thank you..!