32.The & and * Operators in POINTER

Consider the declaration,

int i=5;

This declaration tells the C compier to

• Reserve space in memory to hold the integer value.
• Associate the name i with this memory location.
• Store the value 3 at this location.

We may represent i's location in the memory by the following memory map:

we see that the computer has selected memory location 6589 as the place to store the value 5. This location number 6589 is not a number to be relied upon, becuse some othertime the computer may choose a different location for storring the value 5. The important point is, i's address in memory is a number.

We can print this adderss through the following program:

#include<stdio.h>

main( )

{

int i=5;

printf("\n Address of i=%u", &i);

printf("\n Value of i=%u", i);

getch();

}

The output of the above program would be:

Address of i=6589

Value of i=5

Now look at the first printf( ) statement carefully. The '&' operator used in this statement is C's 'address of' operator. The expression &i returns the address of the variable i, which in this case happens to be 6589.

The other pointer operator available in Cis '*', called 'value at address' operator. It returns the value stored at a porticular address. The 'value at address' operator is also called an 'indirection' operator.

post by Arnob.

taken from 'Understanding pointers In C'