What is dereferencing pointer?

Answer 1

They're related but not totally comparable.

A pointer is an address in memory where a variable is located.

An array is a conceptual data representation consisting of a list of more than one item of a particular scalar type (int, float, char, structure, etc.) where each element is accessed by its index. The index can be thought of as a counter or enumerator telling you how many elements you have to skip over to get to the one you're interested in. Here's where addresses come in ... the location of a particular element in memory is offset from the so-called base address (i.e. the address of the starting element) by the value

(sizeof(one element) * index #)

The C compiler is smart enough to take the sizeof() into account when you do pointer arithmetic, so you can find the address of the i-th element as (address of base) + i, rather than having to do the multiplication explicitly.

The idea of element address as offset also accounts for C's use of zero-relative array definitions. Since the first element is offset by 0 positions from the first element its index in C is 0, not 1. The second (ordinal) element is offset from the first by 1 position so its index is 1, and so on.

Answer 2

The difference that i learnt very recently and the one i remember :-)

Reference cannot be changed whereas pointer value can be changed.

Actually, const pointer = reference.

Answer 3

There is a difference: a pointer is a number that literally points to a place in memory. Arrays are groupings of a type. There is a close relationship between pointers and arrays, however: every expression with arrays (example: array[i]) can be expressed with pointers (example: *(array + i)), because for the computer, an array is just a list of pointers to the type of the array.

Answer 4

1. A pointer when declared uses additional memory. e.g.

int a=10;

int *ptr=&a;

Here, to store the address of 'a', ptr needs an additional memory.

On the contrary, a reference variable can be assumed to be just another name

given to an existing variable. Hence, it requires no additional memory as it isn't

storing any address.

2. A reference variable needs to be initialized when declared. No such case with pointers. e.g.

int a=10,*ptr; // Works fine

int &b; // Error.

3. A pointer after initialization can be re-initialized, whereas a reference variable cannot. e.g.

int a=10, b=20, *p;

int &c=a;

p=&a; // Fine.

p=&b; // Fine.

&c=b; // Error.

Answer 5

A pointer is an object that contains the address of another object.

A deference'ed pointer is an object. It was a pointer, but its address was used to locate and use that other object as if it was the original target of the instruction.

Answer 6

A pointer is a variable that stores a memory address. We say the variable "points-to" that memory address. A memory address is also known as a reference. Dereferencing a memory address returns the value stored at that address.

Consider the following:

int i = 42;

When we use i we are referencing the memory where the value 42 is stored. To obtain the actual memory address itself we use the address-of operator (&) which allows us to store that memory address in a pointer variable:

int* p = &i;

Since p is a variable it has an address of its own, &p. The value of p is the address of i. In order to access the value of i through p, we must dereference p with the dereference operator, *p. Thus &i returns the address of i while i itself returns the value of i, 42. &p returns the address of p, p returns the value of p, which is the address of i and *p returns the dereferenced value of p, which is 42, the value stored at address &i.

Answer 7

--> Array is a collection of same kind of data.

--> Pointer is a memory location where the data stored in the memory

Answer 8

Well, the pointer is a type of variables that stores an address in the Memory.

the reference is the address itself of a variable.

Answer 9

arrays are the reserved sets of variables, which are supposed to store the similar data.

pointers are the special variables which store the address of other variables.