Pointer(Introduction )

Pointer

Introduction

Pointers are a fundamental part of C. If you cannot use
pointers properly then you have basically lost all the power
and flexibility that C allows. The secret of C is in its use of pointers.

C uses pointers a lot. Why?

It is the only way to express some computations.

It produces compact and efficient code.

It provides a very powerful tool.

C uses pointers explicitly with following:

1. Functions.
2. Arrays.
3. Structures. (discussed later)

Note: Pointers are perhaps the most difficult part of C
to understand. C's implementation is slightly different
from other languages.

What is a Pointer?

A pointer is a variable which can hold the address of a memory
location rather than the value at the location.

Pointer Notation

The actual address of a variable is not known immediately.
We can determine the address of the variable using address
of operator(&).

We have already seen the use of address of operator in the scanf() function.

Another pointer operator available in C is "*" called
"value of address" operator. It gives the value stored at a
particular address. This operator is also known as indirection operator.

Pointer Declaration

To declare a pointer to a variable:

int *pointer;

Note: We must associate a pointer to a particular type:
You can't assign the address of a short int to a long int,