Here is a simple rule when to define objects on the heap and when to do it on the stack. The stack is much more efficient than the heap. Simple rule: Use the stack when you can. You cannot use the stack if you need the object in other functions. (Stack allocations are deleted when [...]

In MFC program, you’d better try to avoid using std::string. There is no compelling reason to use it in MFC, and it leads to confusion. There are some standard method to translate among Cstring ,string and char[]. // Suppose CString str; std::string s; char buf[SIZE]; // from CString to std::string s = str; // from [...]