(WINAPI) KM -> M

#include <Windows.h>
#include <math.h>
#include <list>
#include <stdio.h>

using namespace std;

LPCSTR NazwaKlasy = TEXT("Klasa Okienka");
MSG Komunikat;
HDC hdc;
HWND hwnd;
RECT Rect;
HWND hRadio1, hRadio2, hText1, hText2, hText3, hText4;
LRESULT CALLBACK WndProc(HWND hwnd, UINT msg, WPARAM wParam, LPARAM lParam);
char buff1[50], buff2[50], buff3[50], buff4[50];
float value,value2;

int WINAPI WinMain(HINSTANCE hInstance, HINSTANCE hPrevInstance, LPSTR lpCmdLine, int nCmdShow)
{
    WNDCLASSEX wc;
    wc.cbSize = sizeof(WNDCLASSEX);
    wc.style = CS_HREDRAW | CS_VREDRAW;
    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 = NazwaKlasy;
    wc.hIconSm = LoadIcon(NULL, IDI_APPLICATION);

    if (!RegisterClassEx(&wc))
    {
        MessageBox(NULL, TEXT("Nie mozna utworzyc okna"), TEXT("Niestety..."),
            MB_ICONEXCLAMATION | MB_OK);
        return 1;
    }

    hwnd = CreateWindowEx(WS_EX_CLIENTEDGE, NazwaKlasy, TEXT("Oto okienko"), WS_OVERLAPPEDWINDOW,
        CW_USEDEFAULT, CW_USEDEFAULT, 800, 600, NULL, NULL, hInstance, NULL);

    hRadio1 = CreateWindowEx(0, "BUTTON", "KM na METRY", WS_CHILD | WS_VISIBLE | BS_CHECKBOX,
        100, 100, 150, 30, hwnd, (HMENU)1, hInstance, NULL);
    hRadio2 = CreateWindowEx(0, "BUTTON", "METRY na KM", WS_CHILD | WS_VISIBLE | BS_CHECKBOX,
        100, 100, 150, 30, hwnd, (HMENU)2, hInstance, NULL);
    hText1 = CreateWindowEx(0, "EDIT", NULL, WS_CHILD | WS_VISIBLE | WS_BORDER, 50, 50, 150, 20,
        hwnd, NULL, hInstance, NULL);
    hText3 = CreateWindowEx(0, "Static", NULL, WS_CHILD | WS_VISIBLE | WS_BORDER, 50, 50, 150, 20,
        hwnd, NULL, hInstance, NULL);


    if (hwnd == NULL)
    {
        MessageBox(NULL, TEXT("Okno odmówiło przyjścia na świat!"), TEXT("Ale kicha..."), MB_ICONEXCLAMATION);
        return 1;
    }

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

    while (GetMessage(&Komunikat, NULL, 0, 0))
    {
        TranslateMessage(&Komunikat);
        DispatchMessage(&Komunikat);
    }
    return Komunikat.wParam;
}
LRESULT CALLBACK WndProc(HWND hwnd, UINT msg, WPARAM wParam, LPARAM lParam)
{


    switch (msg)
    {
    case WM_COMMAND:

        if ((HWND)lParam == hRadio1)
        {
            CheckRadioButton(hwnd, 1, 2, 1);
        }

        if ((HWND)lParam == hRadio2)
        {
            CheckRadioButton(hwnd, 1, 2, 2);
        }

        if ((IsDlgButtonChecked(hwnd, 1) == BST_CHECKED) == 1)
        {
            GetWindowText(hText1, buff1, 50);
            value = atof(buff1);
            value *= 1000;
            sprintf_s(buff1, "%.02f", value);
            SetWindowText(hText3, buff1);
        }

        if ((IsDlgButtonChecked(hwnd, 2) == BST_CHECKED) == 1)
        {
            GetWindowText(hText1, buff1, 50);
            value = atof(buff1);
            value /= 1000;
            sprintf_s(buff1, "%.02f", value);
            SetWindowText(hText3, buff1);
        }
        break;
    case WM_CREATE:
        break;
    case WM_CLOSE:
        DestroyWindow(hwnd);
        break;
    case WM_DESTROY:
        PostQuitMessage(0);
        break;

    case WM_SIZE:
        GetClientRect(hwnd, &Rect);
        MoveWindow(hText1, Rect.right / 2 - 150, Rect.bottom / 2 - 50, 80, 20, TRUE);
        MoveWindow(hText3, Rect.right / 2 + 80, Rect.bottom / 2 - 50, 80, 20, TRUE);
        MoveWindow(hRadio1, Rect.right / 2 - 60, Rect.bottom / 2 - 50, 120, 20, TRUE);
        MoveWindow(hRadio2, Rect.right / 2 - 60, Rect.bottom / 2 - 30, 120, 20, TRUE);
        break;
    default:
        return DefWindowProc(hwnd, msg, wParam, lParam);
    }

    return 0;
}