Three kinds of references

We describe and contrast the three kinds of references in C++

Using formulations and wordings from The C++ Prog. Lang. (4. edition)

Lvalue references
- Refers to values we want to change
- Useful alternatives for C-style 'call by reference' parameters (using pointers)
const Lvalue references
- Refers to constants - values that we do not want to change
- Useful alternative for 'call by value' parameters in many contexts
Rvalue references
- Refer values that we do not want to preserve after we have used it
- Useful in the context of value return from a function
- Values that we intend to 'move from'