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#include <windows.h>
#include <stdlib.h>

#define MY_CLASS TEXT("my_class")

#define BUTTON_RUN 0
#define TEXT_DEC   1
#define LABEL_BIN  2

HWND lblBin, txtDec;

LRESULT CALLBACK WindowProc(
        HWND hWnd, UINT msg, WPARAM wp, LPARAM lp)
{
    switch(msg){
        case WM_COMMAND:
            if(LOWORD(wp) == BUTTON_RUN){
                /***************************************************
                //２進数に変換する
                ****************************************************/
                TCHAR jyuStr[255];
                TCHAR nisinStr[17];
                TCHAR tmp[2];
                int nisin[16];
                int jyu;
                int i;

                //入力した数値を受け取る
                GetWindowText(txtDec, jyuStr, lstrlen(jyuStr));
                jyu = atoi(jyuStr);

                //変換
                for(i=0; i<16; i++){
                    nisin[i] = jyu % 2;
                    jyu = jyu - 2;
                }

                //文字列に直す
                itoa(nisin[15], tmp, 2);
                lstrcpy(nisinStr, tmp);
                for(i=14; i>=0; i--){
                    itoa(nisin[i], tmp, 2);
                    lstrcat(nisinStr, tmp);
                }

                //表示
                SetWindowText(lblBin, nisinStr);
                /****************************************************/
            }

            break;
        case WM_DESTROY:
            PostQuitMessage(0);
            break;
        default:
            return DefWindowProc(hWnd, msg, wp, lp);    
    }

    return 0;
}

int WINAPI WinMain(
        HINSTANCE hInstance, HINSTANCE hPrevInstance,
        LPSTR lpCmdLine, int nCmdShow)
{
    MSG msg;
    WNDCLASS wc;
    HWND hWnd;

    wc.cbClsExtra = 0;
    wc.cbWndExtra = 0;
    wc.hbrBackground = (HBRUSH)GetStockObject(WHITE_BRUSH);
    wc.hCursor = LoadCursor(NULL, IDC_ARROW);
    wc.hIcon = LoadIcon(NULL, IDI_APPLICATION);
    wc.hInstance = hInstance;
    wc.lpfnWndProc = WindowProc;
    wc.lpszClassName = MY_CLASS;
    wc.lpszMenuName = NULL;
    wc.style = CS_VREDRAW | CS_HREDRAW;

    if(!RegisterClass(&wc)){ return 0; }

    hWnd = CreateWindow(
        MY_CLASS, TEXT("10進数→2進数"), 
        WS_OVERLAPPEDWINDOW | WS_VISIBLE,
        CW_USEDEFAULT, CW_USEDEFAULT,
        230, 69,
        NULL, NULL, hInstance, NULL);

     txtDec = CreateWindow(
        TEXT("EDIT"), TEXT(""),
        WS_CHILD | WS_VISIBLE | WS_BORDER,
        0, 0, 150, 20,
        hWnd, (HMENU)TEXT_DEC, hInstance, NULL);

     lblBin = CreateWindow(
         TEXT("STATIC"), TEXT(""),
         WS_CHILD | WS_VISIBLE,
         0, 20, 150, 20,
         hWnd, (HMENU)LABEL_BIN, hInstance, NULL);

     CreateWindow(
        TEXT("BUTTON"), TEXT("実行"),
        WS_CHILD | WS_VISIBLE | BS_PUSHBUTTON,
        150, 0, 80, 40,
        hWnd, (HMENU)BUTTON_RUN, hInstance, NULL);

    if(hWnd == NULL){ return 0; }

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

    return (int)msg.wParam;
}