[핵심 API로 배우는 윈도우프로그래밍(강경우, 한빛아카데미)] 7장 6번 풀이

#include <Windows.h>
#include<tchar.h>
#include<string.h>
#include<math.h>
//#pragma comment(linker,"/entry:WinMainCRTStartup /subsystem:console")
LRESULT CALLBACK WndProc(HWND hwnd, UINT iMsg, WPARAM wParam, LPARAM lParam);
HINSTANCE hInst;
 
int WINAPI WinMain(HINSTANCE hInstance, HINSTANCE hPrevInstance, LPSTR lpszCmdLine, int nCmdShow)
{
    HWND hwnd;
    MSG msg;
    WNDCLASS WndClass;
 
    hInst = hInstance;
    WndClass.style = CS_HREDRAW | CS_VREDRAW;
    WndClass.lpfnWndProc = WndProc;
    WndClass.cbClsExtra = 0;
    WndClass.cbWndExtra = 0;
    WndClass.hInstance = hInstance;
    WndClass.hIcon = LoadIcon(NULL, IDI_APPLICATION);
    WndClass.hCursor = LoadCursor(NULL, IDC_ARROW);
    WndClass.hbrBackground = (HBRUSH)GetStockObject(WHITE_BRUSH);
    WndClass.lpszMenuName = NULL;
    WndClass.lpszClassName = _T("Window Class Name");
 
    RegisterClass(&WndClass);
 
    hwnd = CreateWindow(
        _T("Window Class Name"),
        _T("박정호"),
        WS_OVERLAPPEDWINDOW,
        50,
        50,
        1000,
        700,
        NULL,
        NULL,
        hInstance,
        NULL);
 
    ShowWindow(hwnd, nCmdShow);
    UpdateWindow(hwnd);
 
    while (GetMessage(&msg, NULL, 0, 0))
    {
        TranslateMessage(&msg);
        DispatchMessage(&msg);
    }
    return (int)msg.wParam;
}
#define IDC_EDIT1 100
#define IDC_EDIT2 101
#define IDC_EDIT3 102
#define IDC_BUTTON1 103
#define IDC_BUTTON2 104
#define IDC_BUTTON3 105
#define IDC_BUTTON4 106
LRESULT CALLBACK WndProc(HWND hwnd, UINT iMsg, WPARAM wParam, LPARAM lParam)
{
    HDC hdc;
    static HWND hEdit1, hEdit2, hEdit3,hButton1, hButton2, hButton3, hButton4;
    double num1, num2, result;
    TCHAR tmp[20];
    switch (iMsg)
    {
    case WM_CREATE:
        hEdit1 = (HWND)CreateWindow(_T("edit"), NULL, WS_CHILD | WS_VISIBLE | WS_BORDER, 80, 70, 80, 20, hwnd, (HMENU)IDC_EDIT1, hInst, NULL);
        hEdit2 = (HWND)CreateWindow(_T("edit"), NULL, WS_CHILD | WS_VISIBLE | WS_BORDER, 200, 70, 80, 20, hwnd, (HMENU)IDC_EDIT2, hInst, NULL);
        hEdit3 = (HWND)CreateWindow(_T("edit"), NULL, WS_CHILD | WS_VISIBLE | WS_BORDER, 100, 170, 150, 20, hwnd, (HMENU)IDC_EDIT3, hInst, NULL);
        hButton1 = (HWND)CreateWindow(_T("button"), _T("+"), WS_CHILD | WS_VISIBLE | BS_PUSHBUTTON, 100, 100, 50, 20, hwnd, (HMENU)IDC_BUTTON1, hInst, NULL);
        hButton2 = (HWND)CreateWindow(_T("button"), _T("-"), WS_CHILD | WS_VISIBLE | BS_PUSHBUTTON, 200, 100, 50, 20, hwnd, (HMENU)IDC_BUTTON2, hInst, NULL);
        hButton3 = (HWND)CreateWindow(_T("button"), _T("X"), WS_CHILD | WS_VISIBLE | BS_PUSHBUTTON, 100, 130, 50, 20, hwnd, (HMENU)IDC_BUTTON3, hInst, NULL);
        hButton4 = (HWND)CreateWindow(_T("button"), _T("/"), WS_CHILD | WS_VISIBLE | BS_PUSHBUTTON, 200, 130, 50, 20, hwnd, (HMENU)IDC_BUTTON4, hInst, NULL);
 
        break;
    case WM_COMMAND:
        switch (LOWORD(wParam))
        {
        case IDC_BUTTON1:
            num1=GetDlgItemInt(hwnd, IDC_EDIT1, NULL, TRUE);
            num2 = GetDlgItemInt(hwnd, IDC_EDIT2, NULL, TRUE);
            result = num1 + num2;
            SetDlgItemInt(hwnd, IDC_EDIT3, result, TRUE);
            break;
        case IDC_BUTTON2:
            num1 = GetDlgItemInt(hwnd, IDC_EDIT1, NULL, TRUE);
            num2 = GetDlgItemInt(hwnd, IDC_EDIT2, NULL, TRUE);
            result = num1 - num2;
            SetDlgItemInt(hwnd, IDC_EDIT3, result, TRUE);
            break;
        case IDC_BUTTON3:
            num1 = GetDlgItemInt(hwnd, IDC_EDIT1, NULL, TRUE);
            num2 = GetDlgItemInt(hwnd, IDC_EDIT2, NULL, TRUE);
            result = num1 * num2;
            SetDlgItemInt(hwnd, IDC_EDIT3, result, TRUE);
            break;
        case IDC_BUTTON4:
            num1 = GetDlgItemInt(hwnd, IDC_EDIT1, NULL, TRUE);
            num2 = GetDlgItemInt(hwnd, IDC_EDIT2, NULL, TRUE);
            result = num1 / num2;
            _stprintf_s(tmp, 20, _T("%lf"), result);
            SetDlgItemText(hwnd, IDC_EDIT3, tmp);
            break;
        }
        break;
    case WM_DESTROY:
        PostQuitMessage(0);
        break;
 
    }
    return DefWindowProc(hwnd, iMsg, wParam, lParam);
}