What Pointer in Data Structure?

Answer 1

No, pointer is not a data type but a reference to an object. Pointers are used to refer back to an object which can be anything from a large data value or a collection of values or objects.

A pointer is a variable and is 4 bytes long because 4 bytes = 32 bits, and all addresses in 32 bit operating systems are 4 bytes long :) , so if you want to store an address somewhere you need 4 bytes. A pointer is just 4 bytes in the memory and in these 4 bytes an address is stored.

If you ask the address of an element, like char, int, etc., the address you will get will be the address of the first byte. Only the first byte is saved in the pointer, and then you can manipulate the upcoming bytes.

For example you declare a structure of 12 bytes and you name it myStruct.
let's say that the address of this structure is the address 0x00400001 <- this is the 1st byte.
The second is 0x00400002 and so on till the 12th byte which is 0x0040000C.

Then you declare a pointer to point to myStruct like that:
myStruct *pointer;
The variable pointer is 4 bytes. It doesn't matter if the structure is 12 bytes or 100 bytes or 1 byte. The address of anything in 32-bit systems is always 4 bytes.
In this example the pointer variable contains the address of myStruct which is 0x00400001 <- the 1st byte of the structure.

The pointer might be a data structure because like any other data types, the pointer is always 4 bytes (in 32-bit systems). For 64bits systems which is 8 bytes, the pointers of a 32bit program would logically be the half of them empty like 0x00000000 00400001

Answer 2

struct S1 {

int fld;

};

struct S1 *p;

typedef struct S2 {

int fld;

} S2;

S2 *p;

typedef struct S3 {

int fld;

} S3, *S3PTR;

S3PTR p;

Answer 3

In a "single linked" linked list it is to point to the next node as the node, bear in mind that the only way to traverse from the previous node to the next node is the pointer, I guess you can kind of think of the data structure like a series of destinations only reachable by one way streets. This makes linked list have a higher big O complexity when retrieving elements, but it makes shifting / insertion much faster, because linked lists pointers can easily be moved.

Answer 4

No, but you can define pointers to primitive (or any) stuctures.

Answer 5

try this, and you will know:

int i;
pointer p;
double d;

Answer 6

It is not exactly a data-type, it is rather a data-type-constructor; for example pointer-to-integer is a data-type.

Answer 7

For example the structure of a binary tree is often represented by pointers:

typedef struct TreeNode {

struct TreeNode *left, *right;

int Data;

} TreeNode;

Answer 8

A pointer is not a structure (primitive or otherwise).

Answer 9

void pointer can point to any data type, however each time it would require typecasting to be done for the appropriate type.