Address operator:

Once we declare a pointer variable we must point it to something we can do this by assigning to the pointer the address of the variable you want to point as in the following example:

ptr=#

This places the address where num is stores into the variable ptr. If num is stored in memory 21260 address then the variable ptr has the value 21260.

/* A program to illustrate pointer declaration*/

main()
{
int *ptr;
int sum;
sum=45;
ptr=∑
printf (“\n Sum is %d\n”, sum);
printf (“\n The sum pointer is %d”, ptr);
}