Pointer to Pointer

A pointer to a pointer stores address of another pointer i.e it points to a pointer.

Representation

type** var_name;

type denotes that it points to pointer to a variable of which type.

Datatype of pointer to a pointer is type**

A quick code snippet

Here's a quick code snippet to make you comfortable with the notations

int **p2p,*ptr,a=300;

ptr=&a;

p2p=&ptr;

printf("%p %p %p",ptr,p2p,&p2p);

Here's a quick picture of address and values of different variables.

           p2p                 ptr                  a

Address  0xbfab60e4         0xbfab60e8          0xbfab60ec

Value    0xbfab60e8         0xbfab60ec             300

p2p------------>ptr---------->a

-> is read as points to and a variable points to another if it stores the address of another.

Value of a can be retreived by **p2p