Przlicznik WORKING

#include <Windows.h>
#include <stdio.h>
#include <cstdio>
#include <tchar.h>

#define INPUT_ID 100
#define RADIO1_ID 101
#define RADIO2_ID 102
#define OUTPUT_ID 103

#define MIN_SIZE_X 500
#define MIN_SIZE_Y 500
#define CONVERSION_FACTOR 2.54
#define CONVERT_TYPE_1 "Cale"
#define CONVERT_TYPE_2 "Centymetry"

RECT WndRect;
HWND hwnd , Input, Radio_1, Radio_2, Output;

//SendMessage(radio1, BM_GETCHECK, 0, 0) == 1;
LRESULT CALLBACK WndProc(HWND hwnd, UINT msg, WPARAM wParam, LPARAM lParam) {
    switch (msg) {
    case WM_COMMAND: {}break;

    case WM_TIMER: {
        char buff[255];
        GetWindowText(Input, buff, 255);
        float Number = 0.0;

        if (SendMessage(Radio_1, BM_GETCHECK, 0, 0) == 1) {
            Number = atof(buff) * CONVERSION_FACTOR;
        }else if (SendMessage(Radio_2, BM_GETCHECK, 0, 0) == 1) {
            Number = atof(buff) / CONVERSION_FACTOR;
        }

        sprintf_s(buff, "%f", Number);
        SetWindowText(Output, buff);

    }break;

    case WM_SIZE: {
        GetClientRect(hwnd, &WndRect);

        MoveWindow(Input,   (WndRect.right / 2) - 100, (WndRect.bottom / 2) - 80, 200, 30, 1);
        MoveWindow(Radio_1, (WndRect.right / 2) - 100, (WndRect.bottom / 2) - 40, 200, 30, 1);
        MoveWindow(Radio_2, (WndRect.right / 2) - 100, (WndRect.bottom / 2)     , 200, 30, 1);
        MoveWindow(Output,  (WndRect.right / 2) - 100, (WndRect.bottom / 2) + 40, 200, 50, 1);

        MapWindowPoints(0, GetParent(hwnd), (LPPOINT)&WndRect, 2);

        if (WndRect.right <= MIN_SIZE_X) {
            MoveWindow(hwnd, WndRect.left, WndRect.top, MIN_SIZE_X+1, WndRect.bottom - WndRect.top, 1);
        }
        if (WndRect.bottom <= MIN_SIZE_Y) {
            MoveWindow(hwnd, WndRect.left, WndRect.top, WndRect.right - WndRect.left, MIN_SIZE_Y+1, 1);
        }

    }break;

    case WM_CLOSE: DestroyWindow(hwnd); break;
    case WM_DESTROY: PostQuitMessage(0); break;
    default: return DefWindowProc(hwnd, msg, wParam, lParam);
    }
    return 0;
}

int WINAPI WinMain(HINSTANCE hInstance, HINSTANCE hPrevInstance, LPSTR ilCmdLine, int nCmdShow) {
    WNDCLASSEX window;
    MSG msg;
    TCHAR Class_Name[] = TEXT("OKNO_TEST"), Title[] = TEXT("Tytul");

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

    RegisterClassEx(&window);

    hwnd = CreateWindowEx(WS_EX_WINDOWEDGE, Class_Name, Title, WS_OVERLAPPEDWINDOW | WS_VISIBLE, CW_USEDEFAULT, CW_USEDEFAULT, 800, 600, NULL, NULL, hInstance, NULL);

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

    GetClientRect(hwnd, &WndRect);

    Input = CreateWindowEx(WS_EX_WINDOWEDGE, "EDIT", NULL, WS_CHILD | WS_VISIBLE | WS_BORDER,
        (WndRect.right / 2) - 100, (WndRect.bottom / 2) - 80, 200, 30, hwnd, (HMENU)INPUT_ID, hInstance, NULL);

    Radio_1 = CreateWindowEx(WS_EX_WINDOWEDGE, "BUTTON", CONVERT_TYPE_1, WS_CHILD | WS_VISIBLE | BS_AUTORADIOBUTTON | WS_GROUP,
        (WndRect.right / 2) - 100, (WndRect.bottom / 2) - 40, 200, 30, hwnd, (HMENU)RADIO1_ID, hInstance, NULL);
    Radio_2 = CreateWindowEx(WS_EX_WINDOWEDGE, "BUTTON", CONVERT_TYPE_2, WS_CHILD | WS_VISIBLE | BS_AUTORADIOBUTTON,
        (WndRect.right / 2) - 100, (WndRect.bottom / 2)     , 200, 30, hwnd, (HMENU)RADIO2_ID, hInstance, NULL);

    Output = CreateWindowEx(WS_EX_WINDOWEDGE, "STATIC", "WYNIK", WS_CHILD | WS_VISIBLE,
        (WndRect.right / 2) - 100, (WndRect.bottom / 2) + 40, 200, 50, hwnd, (HMENU)OUTPUT_ID, hInstance, NULL);

    SendMessage(Radio_1, BM_SETCHECK, 1, 0);

    SetTimer(hwnd, 1, 200, NULL);

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

    UnregisterClass(Class_Name, hInstance);
    return msg.wParam;
}