Difference between int f(int *i) and int f(int &i)

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What are the differences between pointer variable and reference variable in C++?
Pointer vs. Reference

To do a call-by-reference in C++, I think I could use either of those two:

int f(int *x);
int g(int &x);

They would be called like so:

int *w;
f(w);
g(*w);

int y;
f(&y);
g(y);

Is there a difference in the functions f and g? I should be able to work with x as an int* pointer and *x as an int inside both functions. So what is the difference?

The former is a pointer, the latter is a reference. There is a huge difference between the two. (Also removed the C tag since references don't exist in C) — netcoder, Dec 20 '12 at 15:52
This may help you : [differences between pointer variable and reference](http://stackoverflow.com/questions/57483/what-are-the-differences-between-pointer-variable-and-reference-variable-in-c-) — Passepartout, Dec 20 '12 at 15:54

Will · Accepted Answer · 2012-12-20T15:57:47.453

3

Most of this is a matter of taste. There is one important difference though. A pointer (*) can have a null value whereas a reference cannot be null and always must refer to a valid object.

edited Dec 20 '12 at 15:57

answered Dec 20 '12 at 15:52

Will

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"or null in cpp" what is cpp for you? or did you mean C++ and nullptr? – PlasmaHH Dec 20 '12 at 15:54
yes I meant `nullptr`. I've updated it now – Will Dec 20 '12 at 15:56
...and by cpp/C++ I take it you mean C++11? – netcoder Dec 20 '12 at 15:56
Ok, no reference to individual null values or lanugages any more. Hopefully this should stop any confusion – Will Dec 20 '12 at 15:58

score 2 · Answer 2 · answered Dec 20 '12 at 15:52

2

The reference can't be NULL, so you don't have to check that. Otherwise, it's probably just syntactic sugar (at least for simple use cases). Check the disassembly of your program to see.

answered Dec 20 '12 at 15:52

Carl Norum

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Difference between int f(int *i) and int f(int &i)

2 Answers2