很多时候大家需要在程序中发送邮件，自己编又太麻烦，怎么办，呵呵，有现成的！

1、想省事儿的，用ShellExecute函数：

ShellExecute(NULL,NULL,"mailto:email@{域名已经过期}",NULL,NULL,SW_SHOW);

2、如果想自己多处理一些东西的话，比如加上默认的帐号、密码、附件等，就可以调用系统的Mapi函数。具体的用法大家可以去查MSDN都是以MAPI开头的，如MAPILogon、MAPISendMail等。下面这段代码演示如何调用默认的邮件程序发送邮件。

#include "mapi.h"                    

void CTestMapiDlg::OnSendMail()
{
HMODULE hMod = LoadLibrary("MAPI32.DLL");

if (hMod == NULL)
{
AfxMessageBox(AFX_IDP_FAILED_MAPI_LOAD);
return;
}

ULONG (PASCAL *lpfnSendMail)(ULONG, ULONG, MapiMessage*, FLAGS, ULONG);
(FARPROC&)lpfnSendMail = GetProcAddress(hMod, "MAPISendMail");

if (lpfnSendMail == NULL)
{
AfxMessageBox(AFX_IDP_INVALID_MAPI_DLL);
return;
}

ASSERT(lpfnSendMail != NULL);

TCHAR szPath[_MAX_PATH] = "C:\\Winnt\\setup.log";
TCHAR szTitle[_MAX_PATH] = "setup.log";

// prepare the file description (for the attachment)
MapiFileDesc fileDesc;
memset(&fileDesc, 0, sizeof(fileDesc));
fileDesc.nPosition = (ULONG)-1;

fileDesc.lpszPathName = szPath;
fileDesc.lpszFileName = szTitle;

// prepare the message (empty with 1 attachment)
MapiMessage message;
memset(&message, 0, sizeof(message));
message.nFileCount = 1;
message.lpFiles = &fileDesc;

int nError = lpfnSendMail(0, 0,
&message, MAPI_LOGON_UI¦MAPI_DIALOG, 0);

// after returning from the MAPISendMail call, the window must
// be re-enabled and focus returned to the frame to undo the workaround
// done before the MAPI call.
if (nError != SUCCESS_SUCCESS &&
nError != MAPI_USER_ABORT && nError != MAPI_E_LOGIN_FAILURE)
{
   AfxMessageBox(AFX_IDP_FAILED_MAPI_SEND);
}
}