Pointers

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,