Const is only used to distinguish whether to define parameters for references or pointers when defining function signatures. That is, when the parameters of overloaded functions are references or pointers, const declarations are used to distinguish them from value parameters.

For example: long large (const long &; const long & ampb)；

If the parameter is passed by value, Const will be ignored, such as the following two overloaded functions with the same function signature.

Dragon & big (long A, long B);

Dragon & is large (constant length A, constant length B);