How to pass “literal” integers by reference in C++ (Newbie)

Question

Edit: As many people have pointed out, pass-by-reference isn\'t generally appropriate as an optimisation for primitive types. This is excellent to know, so

Answer 1

To avoid the inefficiency of copy-by-value when calling a function

Stop right there.

Passing by reference does not necessarily mean "fast". This goes doubly so for basic types. Indeed, accessing basic types by reference will be slower than doing so by value. A reference is not magic. It's generally implemented as a pointer. So every time you access that value, you are likely doing a pointer dereference.

This sounds like some kind of micro-optimization. Do not optimize without profiling. Unless you have really good reason to expect the performance of your application to hinge on value vs. reference parameters, just do what makes sense.

You should only pass basic types by reference if you intend to modify them.