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A variable that is a pointer to a pointer must be declared as such. This is done by placing
an additional asterisk in front of its name. For example, the following declaration declares a
pointer to a pointer of type int:
When a target value is indirectly pointed to by a pointer to a pointer, accessing that value

int **var;
requires that the asterisk operator be applied twice, as is shown below in the example:

#include <stdio.h>

int main ()
{

int var;
int *ptr;

int **pptr;

var = 3000;

/* take the address of var */
ptr = &var;

/* take the address of ptr using address of operator & */
pptr = &ptr;

/* take the value using pptr */

printf("Value of var = %d\n", var );
printf("Value available at *ptr = %d\n", *ptr );

printf("Value available at **pptr = %d\n", **pptr);

return 0;
}

When the above code is compiled and executed, it produces the following result:

111