drag n drop

#include <Windows.h>

HWND editBox1;
HWND editBox2;

MSG evnt;

LRESULT CALLBACK WndProc(HWND hwnd, UINT msg, WPARAM wParam, LPARAM lParam);

void init(HINSTANCE hInstance, LPSTR className);

int WINAPI WinMain(HINSTANCE hInstance, HINSTANCE hPrevInstance, LPSTR lpCmdLine, int nCmdShow)
{
    // Creating window class
    LPSTR className = "Window Class";
    init(hInstance, className);

    // Creating main window
    HWND hwnd;
    hwnd = CreateWindowEx(WS_EX_CLIENTEDGE, className, "Drag n Drop", WS_OVERLAPPEDWINDOW, CW_USEDEFAULT, CW_USEDEFAULT, 500, 500, NULL, NULL, hInstance, NULL);

    // Error checking
    if (hwnd == NULL)
    {
        MessageBox(NULL, "Could not create window", "", MB_ICONEXCLAMATION);
        return 1;
    }

    ShowWindow(hwnd, nCmdShow); // Pokaż okienko...
    UpdateWindow(hwnd);

    editBox1 = CreateWindowEx(WS_EX_CLIENTEDGE, "EDIT", "", WS_CHILD | WS_VISIBLE, 150, 80, 200, 50, hwnd, (HMENU)1, hInstance, NULL);
    editBox2 = CreateWindowEx(WS_EX_CLIENTEDGE, "EDIT", "", WS_CHILD | WS_VISIBLE, 150, 150, 200, 50, hwnd, (HMENU)2, hInstance, NULL);

    while (GetMessage(&evnt, NULL, 0, 0))
    {
        TranslateMessage(&evnt);
        DispatchMessage(&evnt);
    }
    return evnt.wParam;
}

LRESULT CALLBACK WndProc(HWND hwnd, UINT msg, WPARAM wParam, LPARAM lParam)
{
    switch (msg)
    {
    case WM_COMMAND:
        switch (wParam)
        {
        case 1:
            // Button 1
            break;
        }
        break;

    case WM_CLOSE:
        DestroyWindow(hwnd);
        break;

    case WM_DESTROY:
        PostQuitMessage(0);
        break;

    default:
        return DefWindowProc(hwnd, msg, wParam, lParam);
    }
    return 0;
}

void init(HINSTANCE hInstance, LPSTR className)
{
    WNDCLASSEX wc;

    wc.cbSize = sizeof(WNDCLASSEX);
    wc.style = 0;
    wc.lpfnWndProc = WndProc;
    wc.cbClsExtra = 0;
    wc.cbWndExtra = 0;
    wc.hInstance = hInstance;
    wc.hIcon = LoadIcon(NULL, IDI_APPLICATION);
    wc.hCursor = LoadCursor(NULL, IDC_ARROW);
    wc.hbrBackground = (HBRUSH)(COLOR_WINDOW + 1);
    wc.lpszMenuName = NULL;
    wc.lpszClassName = className;
    wc.hIconSm = LoadIcon(NULL, IDI_APPLICATION);

    // Registering window class
    if (!RegisterClassEx(&wc))
    {
        MessageBox(NULL, "Could not register window!", "", MB_ICONEXCLAMATION | MB_OK);
        return;
    }
}