> no mutable reference parameters Sidenote: The style guide (recently?) removed the ban on non-const references [0]. They are now allowed for non-optional outp

> no mutable reference parameters Sidenote: The style guide (recently?) removed the ban on non-const references [0]. They are now allowed for non-optional output parameters. Though returning value is generally preferred over output parameters. [0] https://google.github.io/styleguide/cppguide.html#Inputs_and_Outputs https://google.github.io/styleguide/cppguide.html#Inputs_and...