程序代码：

#include <windows.h>
#include <windowsx.h>
#include <string.h>
#include "main.h"
#include "dialogs.h"
#include "resource.h"
#include "rsrc.inc"

BOOL WINAPI Main_Proc(HWND hWnd, UINT uMsg, WPARAM wParam, LPARAM lParam)
{
    switch(uMsg)
    {
        //BEGIN MESSAGE CRACK
        HANDLE_MSG(hWnd, WM_INITDIALOG, Main_OnInitDialog);
        HANDLE_MSG(hWnd, WM_COMMAND, Main_OnCommand);
        HANDLE_MSG(hWnd,WM_CLOSE, Main_OnClose);
        //END MESSAGE CRACK
    }

    return FALSE;
}

////////////////////////////////////////////////////////////////////////////////
//  Main_OnInitDialog
BOOL Main_OnInitDialog(HWND hwnd, HWND hwndFocus, LPARAM lParam)
{
    // Set app icons
    HICON hIcon = LoadIcon((HINSTANCE) GetWindowLong(hwnd, GWL_HINSTANCE) ,MAKEINTRESOURCE(IDI_ICONAPP));
    SendMessage(hwnd, WM_SETICON, TRUE,  (LPARAM)hIcon);
    SendMessage(hwnd, WM_SETICON, FALSE, (LPARAM)hIcon);
    
    //
    // Add initializing code here
    //
    
    return TRUE;
}

////////////////////////////////////////////////////////////////////////////////
//  Main_OnCommand
void Main_OnCommand(HWND hwnd, int id, HWND hwndCtl, UINT codeNotify)
{
    TCHAR cDriveExists[]="ABCDEFGHIJKLMNOPQRSTUVWXYZ";
    int nLen=0;
    switch(id)
    {
        case IDC_BTNRESULT:        //响应计算圆面积按钮 
            TCHAR cBanjing[256];
            GetDlgItemText(hwnd,IDC_EDTRADIUS,cBanjing,sizeof(cBanjing)/sizeof(TCHAR));
               double fBanjing,fZhouchang;
            fBanjing = atof(cBanjing);
            fZhouchang = 3.1415926*(fBanjing*fBanjing);
            TCHAR cZhouchang[256];
            gcvt(fZhouchang,10,cZhouchang);
            //SetDlgItemText(hwnd,IDC_EDTZHOUCHANG,cZhouchang);
            SetDlgItemText(hwnd,IDC_STC,cZhouchang);
        break;
        case IDC_BTNCALCHELP:    //响应圆面积帮助按钮
            MessageBox(hwnd,TEXT("\n圆形面积计算公式:\n\n圆面积(s)=圆周率π(3.14)*半径(r)的平方。\t"),TEXT("计算公式"),MB_OK|MB_ICONASTERISK); 
        break;
        case IDC_BTNGETDRIVERS:    //获取用户磁盘信息按钮 
            DWORD dwMydrivers;
            dwMydrivers = GetLogicalDrives();
            TCHAR cDrivers[256];
            itoa(dwMydrivers,cDrivers,2);    //转换为字符串 
            strrev(cDrivers);                //反转字符串 
            TCHAR cDriverscn[256];
            //MessageBox(hwnd,cDrivers,TEXT("调试"),MB_OK);
            
            //列出所有存在盘符 
            int i;
            for(i=0;i<strlen(cDrivers);i++)
            {
                if(cDrivers[i]=='1')
                   {
                      cDriverscn[nLen] = cDriveExists[i];
                      nLen++;
                }
            }
            cDriverscn[nLen]='\0';
            SetDlgItemText(hwnd,IDC_EDTMYDRIVERS,cDriverscn);
            
            //判断是否存在D盘 
            if(cDrivers[4]='1')
            {
                SetDlgItemText(hwnd,IDC_EDTYESNOD,TEXT("有")); 
            }
            else
            {
                SetDlgItemText(hwnd,IDC_EDTYESNOD,TEXT("无"));
            }
            
            //计算存在磁盘总数 
            TCHAR cSUM[256];
            itoa(nLen,cSUM,10);
            SetDlgItemText(hwnd,IDC_EDTDRIVERSNUM,cSUM);
        break;
        
        default:break;
    }

}

////////////////////////////////////////////////////////////////////////////////
//  Main_OnClose
void Main_OnClose(HWND hwnd)
{
    EndDialog(hwnd, 0);
}

Calculator_DriveMessage.rar (1.4 MB)