Pointer to Pointer in C

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In this class, Pointer to Pointer in C.

We have already discussed the concepts of pointers.

Table of Contents

We will try to understand the concept of Pointer to Pointer using an example.

Pointer to Pointer is a pointer variable that stores the address of another pointer.

The image below is an example of Pointer to Pointer.

We will consider each line of the code and visualize every line of code.

int a = 10;

As shown below, we define an integer variable, and the compiler has assigned address 100 for a.

int *p = &a;

Here p is an integer pointer variable storing the address a.

The pointer p is assigned to address 200 by the compiler, as shown below.

int **ptp = &p;

The above statement is the definition of a Pointer to Pointer.

Here ‘ptp’ is a pointer that stores another ‘pointer’ address, which points to an integer variable.

The compiler has assigned ptp at 300 memory locations, as shown below.

printf(“a = %d\n”, a);

The above printf will print the value stored in a, 10.

printf(“*p = %d\n”, *p);

The above printf will print the value stored in the address p is pointing to, 10.

printf(“**ptp = %d\n”, **ptp);

The above **ptp has two indirection operators.

The simplified way of representing the above expression is (ptp).

(*ptp) is 100, and *(100) is 10.