What are the differences between hwnd, HDC, and CDC?

Hwnd is the window handle. You need to use this handle to obtain some properties of the window. HDC is the context handle for window display. It is only required for graphic and text output in the window. Hwnd has a wider application scope. With hwnd, you can use the getdc () function of the API to obtain the HDC related to it.

Cdc dc;
CDC is a class, and DC is an object of it. This class is specially used to encapsulate HDC. For example
DC. Attach (HDC); then the system object can be operated through DC.

 

Cdc dc (this );

HDC;

HDC = Dc-> m_hdc;