Can i put my window code in function or header - c++

Question

I have this code for crearing a window and i was wondering if i could put it in aheader or in a separate function to optimize my projects. And if so, could I manipulate its size and content from the separate program The code is:
#include <windows.h>
#include <windowsx.h>
LRESULT CALLBACK WindowProc(HWND hWnd,
UINT message,
WPARAM wParam,
LPARAM lParam);
int WINAPI WinMain(HINSTANCE hInstance,
HINSTANCE hPrevInstance,
LPSTR lpCmdLine,
int nCmdShow)
{
HWND hWnd;
WNDCLASSEX wc;
ZeroMemory(&wc, sizeof(WNDCLASSEX));
wc.cbSize = sizeof(WNDCLASSEX);
wc.style = CS_HREDRAW | CS_VREDRAW;
wc.lpfnWndProc = WindowProc;
wc.hInstance = hInstance;
wc.hCursor = LoadCursor(NULL, IDC_ARROW);
wc.hbrBackground = (HBRUSH)COLOR_WINDOW;
wc.lpszClassName = "WindowClass1";
RegisterClassEx(&wc);
hWnd = CreateWindowEx(NULL, "WindowClass1",
"Our First Windowed Program",
WS_OVERLAPPEDWINDOW,
300,
300,
500,
400,
NULL,
NULL,
hInstance,
NULL);
ShowWindow(hWnd, nCmdShow);
MSG msg;
while(GetMessage(&msg, NULL, 0, 0))
{
TranslateMessage(&msg);
DispatchMessage(&msg);
}
return msg.wParam;
}
LRESULT CALLBACK WindowProc(HWND hWnd, UINT message, WPARAM wParam, LPARAM lParam)
{
switch(message)
{
case WM_DESTROY:
{
PostQuitMessage(0);
return 0;
} break;
}
return DefWindowProc (hWnd, message, wParam, lParam);
}