Pointer to Pointer in C++: This can be defined as a form of multiple indirections or a chain of pointers. Normally, a pointer contains the address of a variable. When we define a pointer to a pointer, the first pointer contains the address of the second pointer, which points to the location that contains the actual value. The 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.
Pointer to Pointer in C++
When a target value is indirectly pointed to by a pointer to a pointer, accessing that value requires that the asterisk operator be applied twice.
Example:
#include<iostream>
using namespace std;
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
cout << "Value of var :" << var << endl;
cout << "Value available at *ptr :" << *ptr << endl;
cout << "Value available at **pptr :" << **pptr << endl;
return 0;
}
Output:
Value of var :3000
Value available at *ptr :3000
Value available at **pptr :3000