Pointers of C program

Hello friends...!!! welcome back.We studied arrays in previous post. here we will discuss on pointers. so here we go. 

What is pointer?

                Pointer is  one type of variable which stores the address of another variable as its value.

We know that computer has lots of memory cells which stores the values and each memory cells having an address. Each location in memory stores one byte of data, multi byte data types like integer, float, character double. Let us understand  this concept with an example.

A=1;     

we know that computer cannot stored any value directly.  we assume any variable for doing this and this variable has its own address in the memory cells. Computer find this value via this address. let assume that A=1 is stored in 10 location in the memory cell. So address of this variable is 10.

Variable = A.

Value = 1.

Address = 10.

 Now, if the address of A is  stored in another variable, that variable can be called as a pointer to  variable A because that variable stores the address of variable A as its value.

 Let variable B  store the address of variable A. So B is a pointer of A.

 To describe the memory address of variable, (&) sign is used. So

 B = &A;                    (B is a pointer to A)

 To describe a pointer variable, we will use (*) sign. So

 *B = &A;                (Pointer B is stores the address of variable A)

POINTER DECLARATION:-

                syntax is:      data type   *variable name;

                                                int   *iB;

                                                char   *cB;

                                                float   *fB;

There are some rules  in the pointer. They are as mentioned below:

->Addition of two pointers is not valid.

->Multiplication operation with any number is not valid.

->Increment and Decrement operations are valid.

->Addition and subtraction integer number with pointer variable are valid.

CHAIN OF POINTER:

                Means that it is a pointer variable, which stores the address of another pointer varable.

syntax is:                     data type   **variable to variable;

                                                (**) means that variable to variable is a pointer to pointer of data type.

Eample:

                                Int a=2;

                                Int *b =&a;

                                Int **c=&b;

Here C stores the address of variable B which is 100 and B stores the address of variable A.

So        *C=B;    and      *B=A;     then   *C=A;

POINTER OF ARRAY:-

Every program written using array can always written with pointers. Following is  array:

Int  a[3];           ==          a[0],a[1], a[2];

Here, array variable works as an address of first element which is a[0]. Variable a[i] is represent in   pointer like *(a+i).

Examples are:      a[0]  or  *(a+0)

                             a[1]  or  *(a+1).

Array of pointer is a collection of pointer known by a single name.

Syntax is:              data type *variable name[size];

Example:                *a[4];     

                                                This concept is used in the pointer.

I hope your basic concept of this topic is clear. If there is any doubt, please feel free to mention it in the comment box. If you are interested you may join our facebook group New Age Informers.

Until then bye bye...!!!!!