C / C++ / MFC

char *stopstring = NULL;
char *number = "1.23e4";
double Double = strtod(number, &stopstring);
 
ASSERT (stopstring != number);
ASSERT (*stopstring == NULL);
ASSERT (Double == 12300.0);

TCHAR szMyCompPath[MAX_PATH];<br />
int rc;<br />
rc = SHGetFolderPath(NULL, CSIDL_DRIVES, NULL, 0, szMyCompPath);

dwFlags
[in] Flags to specify which path is to be returned. It is used for cases where the folder associated with a CSIDL may be moved or renamed by the user. 
SHGFP_TYPE_CURRENT  Return the folder's current path.
SHGFP_TYPE_DEFAULT  Return the folder's default path.

TCHAR szMyCompPath[MAX_PATH];<br />
HRESULT hr;<br />
hr = SHGetFolderPath(NULL, CSIDL_DRIVES, NULL, SHGFP_TYPE_CURRENT, szMyCompPath);

#define _WIN32_WINNT 0x0501
#define STRICT

#include <windows.h>
#include <shlobj.h>
#include <shfolder.h>
#include <tchar.h>

UINT_PTR __stdcall OpenFileHook(HWND hwnd, UINT msg, WPARAM wparam, LPARAM lparam)
{
    if (msg == WM_NOTIFY)
    {
        HWND parent = ::GetParent(hwnd);
        HWND tbctl = ::GetDlgItem(parent, ctl1); // ctl1 is standard ctl id defined in dlgs.h
        LRESULT count = ::SendMessage(tbctl, TB_BUTTONCOUNT, 0, 0);
        LRESULT result;
        for (int button = 0; button < count; ++button)
        {
            TCHAR buttonText[1024];
            TBBUTTON buttonData;
            ::ZeroMemory(buttonText, sizeof(buttonText));
            ::ZeroMemory(&buttonData, sizeof(buttonData));
            result = ::SendMessage(tbctl, TB_GETBUTTON, (WPARAM)button, (LPARAM)&buttonData);
            result = ::SendMessage(tbctl, TB_GETBUTTONTEXT, (WPARAM)buttonData.idCommand, (LPARAM)buttonText);
            if (result != -1 && _tcscmp(_T("My Computer"), buttonText) == 0)
            {
                if (0 == ::SendMessage(tbctl, TB_ISBUTTONCHECKED, (WPARAM)buttonData.idCommand, 0))
                {
                    // tried sending/posting TB_CHECKBUTTON, TB_PRESSBUTTON neither worked
                    // so, instead, 
                    // 1. get client rect of toolbar control and
                    // 2. send WM_LBUTTONDOWN/WM_LBUTTONUP to proper area of toolbar to simulate click
                    //
                    RECT rect;
                    ::ZeroMemory(&rect, 0);
                    ::GetClientRect(tbctl, &rect);

                    // simulate click of button
                    //
                    ::PostMessage(tbctl, WM_LBUTTONDOWN, (WPARAM)MK_LBUTTON, MAKELPARAM(10, (rect.bottom - rect.top)/count * button));
                    ::PostMessage(tbctl, WM_LBUTTONUP, (WPARAM)MK_LBUTTON, MAKELPARAM(10, (rect.bottom - rect.top)/count * button));
                }
            }
        }
    }
    return (UINT_PTR)FALSE;
}

void main()
{
    TCHAR fileBuffer[MAX_PATH * 10];
    OPENFILENAME ofn;
    ZeroMemory(&ofn, sizeof ofn);
    ZeroMemory(fileBuffer, sizeof fileBuffer);

    ofn.lStructSize = sizeof ofn;
    ofn.lpstrFile = fileBuffer;
    ofn.nMaxFile = sizeof(fileBuffer)/sizeof(fileBuffer[0]);
    ofn.Flags = OFN_EXPLORER | OFN_ENABLEHOOK;
    ofn.lpfnHook = OpenFileHook;
    BOOL result = ::GetOpenFileName(&ofn);
}