Pointers in C

 

Concept of pointer

Pointers provide a powerful and flexible way to manipulate data.
When we use a variable in a program the compiler reserves a memory location for that variable.
Example int n=20;
When this statement executes, the compiler  Reserves space in memory to hold an integer value that is 2 bytes for integer variable.
Associates the name ‘n’ with this memory location.
Stores the value 20 at this location.

In the above figure, 2 bytes of memory from address 1002 have been allotted to variable ‘n’ by assuming that an integer requires 2 bytes of storage.
Hence address of variable ‘n’ is 1002.
The address of operator (&)
The ‘&’ operator gives the address of a variable. It is a unary operator which must be written before the variable name.
Syntax: &variable
Example: ptr=&n;
This statement assigns the address of ‘n’ to a  variable called ptr.
Variable and pointer
n ptr
20 1002
1002 2050
In the above example, &n will give 1002.

Explore more in pointers

• What is the pointer
• Value VS Reference Model
• Application of pointers
• Declaring pointers
• Initializing pointers
• Using a pointer 
• Illustrate basic pointer use
• Types of pointers
• Pointer Arithmetic
• Pointer to array
• Relationship between Arrays and Pointers
• Pointer to pointer multiple indirection
• Initializing pointer to pointer
• Functions and Pointers 
• Some pointer declaration and their meaning
• Pointer const and Constant pointer
• Dynamic memory allocation
• Memory allocation for 2D array 
• Memory leaks and dangling pointers
• Static and dynamic memory allocation