Pass by reference pass by pointer

[Analyzer]

What is the difference between.

void gett(int *pointerr){

pointerr += 5;
}

and

void gett(int &referecee){

referencee +=5;
}

When would you choose to pass a variable by "REFERENCE" or by "POINTER".

[LB]

In the one being passed by pointer, you're changing where the pointer points to instead of the data it points to.

[Analyzer]

Really, but it still doesnt answer my question.

if i rewrote it like this..

void gett(int *pointerr){

*pointerr +=5;
}

Than it does the same thing as the pass by reference right?

[LB]

With the difference that the pointer might not be valid.

[Analyzer]

How would a pointer not be valid???

Thanks for your help by the way.

[LB]

If the pointer points to non existant memory, protected memory, out of bounds memory, NULL, etc... the function will crash the application, or just cause corruption.

[Analyzer]

Ok, I was thinking that is what you ment, but I wasn't sure so I asked.

[gcampton]

Have a read:
http://cplusplus.com/forum/articles/20193/

[Analyzer]

Thank You gcampton that helps alot.

[sohguanh]

Actually there is some history I believe in place here. Before C++ is invented, C programmers will use pointer to effect changes on the variables they intend to have before call and then after call a function. Then C++ came along and they introduce reference variables. Actually I would strongly recommend this way but in order to enable C code to run seam-lessly, C++ also accept the pointer notation from the C days.

Generally, for new C++ code I will use reference variables. It is only for legacy code maintenance or the API I am calling uses old C pointer notation would I use pointer variables.