Ting 이네 Software 이야기

* Space vs. Speed
- Most famous one. (Memory space vs. execution speed) - details are omitted.

* Modularity vs. (Performance & Space)
- Well-designed-module should be stable. To be stable, there may be lots of 'parameter check', 'condition check', 'sanity check' and so on. Besides, for the safety reason, it may not trust passed memory space. So, it may allocates it's own memory space and try to copy data from passed memory to use it. Those make this trade-off. Well-designed-module hides it's information and stable as it is. But to be like this, it consumes speed and space.

* Abstraction vs. Debugging
- When software is stable, abstraction reduces maintenance costs very much. But, if not, debugging is more difficult than straightforward designed software, especially, to the engineer who are not accustomed to the software.

* low possibility to misuse vs. various and rich functionality
- It is clear...

* Backward-Compatibility vs. Innovation
- ...

Reference is enhanced concept from Pointer in C++.
So, many C++ books says "Reference is better than Pointer. So try to use Reference if possible."
Yes, reference has several advantages. It guarantees that there is enough memory space for the variable. So, we don't need to do so-called "NULL Check" in most cases (In some evil cases, address can be NULL even if it is reference).
But, in terms of readability, sometimes, using Pointer is better than Reference. Since C, programmers think that parameter is passed by value. Let's see below.

func(a); // --- (*1)
func(&a); // --- (*2)

At first look - before looking at declaration of "func()", programmer tends to think that "Value of 'a' is passed. So, even after (*1), value of 'a' will be preserved." But in case of (*2), they might think that "Address of 'a' is passed. So, after (*2), value of 'a' may be changed."
But, Reference stands against of this 'Popular' concept - reference parameter of 'func()' may change value of 'a'.
But, in case that 'func()' doesn't change 'a', using reference - should be declared as 'const' - as parameter can be good choice.
In other words, if value of parameter is changed, using pointer is better then using reference in terms of readability, in my point of view.

In summary, my recommendation is,

"If possible, use Reference as parameter only when value of parameter is not changed with 'const' keyword."