What is this?

Question

Template <typename x> struct traits

Answer 1

For generic use of classes or functions parameters.When a template is creating with undefined type for generic use later in function or class.This means the data type of argument/s will not be declared only on fonction specialization/call.data type will be int or float etc....Typename or class keywords are used to define generic data type not only one specified data type for a function.So you can later decide of what data type will be the function and its params.