Pointer & Indirection Operator C - Digital College Library

The two fundamental operators used with Pointer are

The address operator returns the address of a variable. The indirection operator returns the value of the variable that the pointer is pointing to.

When a variable x is the declared in a program, a storage location of main memory is made available by the complier as shown below: –

Thus, x is the name associated by the compiler to a location in the memory of the computer.
Let us assume that, at the time of execution, the physical address of this memory location (called x) is 2002
Now, a point worth nothing is that this memory location is viewed by the programmer as variable x and by the operating system as an address 2002.
The address of variable x can be obtained by ‘&’, an address of operator.
This operator when applied to a variable gives the physical memory address of the variable. Thus &x will provide the address 2002.

Consider the following segment: –

     :
  x = 10;
  printf("\n value of x = %d", x);
  printf("\n Address of x =%d", &s);
     :

Once this program segment is obeyed, the output would be: –

Value of x = 10
Address of x = 2002 (assumed value)

It may be noted here that the value of address of x is assumed and the actual value is machine and execution time dependent.

The ‘*’ is an indirection operator or value at address operator.
In simple words, we can say that if address of a variable is known then the ‘*’ operator provides a way of accessing the contents of the variable.

Consider the following segment: –

     :
  x = 10;
  printf("\n Value of x = %d", x);
  printf("\n Address of x = %d", &x);
  printf("\n Value of Address %d=%d", &x, *(&x));
    :

Once the segment is run, the output would be: –

Value of x = 10
Address of x = 2002
Value of Address 2002 = 10

Pointer and Indirection Operator in C Language with Free Notes