Why i can't compare CString in MFC

问题

This line.

UpdateData(true);
if( m_OldPassword.Compare(d.pass) && m_NewPassword.Compare(m_ConfirmPassword) )

m_OldPassword, m_NewPassword, m_ConfirmPassword

is variable i added from EditControl

m_OldPassword.Compare(d.pass) Result =true (tested)

m_NewPassword.Compare(m_ConfirmPassword) Result = false.

IMPLEMENT_DYNAMIC(ChangePassword, CDialog)

ChangePassword::ChangePassword(CWnd* pParent /*=NULL*/)
    : CDialog(ChangePassword::IDD, pParent)
    , m_OldPassword(_T(""))
    , m_NewPassword(_T(""))
    , m_ConfirmPassword(_T(""))
{
}

I dont know what's happen. I sure my input(new, confirm) is right.

回答1:

You need to do

if( m_OldPassword.Compare(d.pass)==0 && m_NewPassword.Compare(m_ConfirmPassword)==0 )

if you are comparing two Cstring say abc and xyz
if abc equal to the string xyz it will return 0
if abc greater than the string xyz it will return 1
if abc less than the string xyz it will return -1

来源：https://stackoverflow.com/questions/27273176/why-i-cant-compare-cstring-in-mfc