Pointers to Pointers
A pointer that stores the address of another pointer:

int a = 10;

int *p = &a;

int **pp = &p;

cout << **pp; // outputs 10

Used in multi-level data structures.

Pointers and Functions
Pointers can be passed to functions to modify values directly.

void update(int *x) {

   *x = 20;

}

int main() {

   int a = 10;

   update(&a);

   cout << a; // 20

}

Also useful for dynamic memory operations.

Pointer to Function

Functions have addresses and can be assigned to pointers.

int add(int a, int b) { return a + b; }

int (*funcPtr)(int, int) = add;

cout << funcPtr(2, 3); // 5

Used in callbacks and event handling.

Constant Pointers vs Pointer to Constant

• Constant Pointer: Pointer cannot change the address.

int a = 5;

int *const ptr = &a;

• Pointer to Constant: Cannot change the value through the pointer.

const int *ptr = &a;