Reference vs. pointer

Question

What is the difference? Because this:

int Value = 50;
int *pValue = &Value;

*pValue = 88;

and ref version do the same:

Answer 1

A pointer is the address of the memory location. You can change the value of that address to point at different memory addresses.

A reference is an alias of the variable. You can only assign this alias during declaration. You cannot change which variable the reference is an alias of after it's declared.

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The following pointer assignments are not possible with references.

int a = 10;
int b = 20;

int* pInt = NULL; // A pointer pointing at nothing.
pInt = &a; // pInt now points at a
pInt = &b; // pInt now points at b

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As for which one is better, it all depends on context.

I use references for method and function parameters.

void updateFoo(Foo& foo)

I use references to alias complex objects.

Foo& foo = bar.getBaz().getFoo(); // easy access to foo

I use pointers for dynamically allocated objects.

Foo* pFoo = new Foo();

I use pointers for things which may point at different values (including no value at all).

Foo* pFoo = NULL;

if (condition1)
    pFoo = &foo1;
else (condition2)
    pFoo = &foo2;

As a general rule, I default to references and use pointers in places where the limitations on references cause problems.