cstring 怎么转换成int

cstring 如何转换成int
CString n1,n2;
GetDlgItemText(num1,n1);
GetDlgItemText(num2,n2); 
int a,b;
a=atoi((char*)(LPCTSTR)n1);
b=atoi((char*)(LPCTSTR)n2);

但是只有第一个数字，比如n1=“12345” 而a=1

------解决方案--------------------------------------------------------
CString m_str;
int num;
num = _ttoi(m_str);