Pointer to Pointer is a straightforward idea in which we store the address of one pointer to another. Because of the operator’s name, this is also known as numerous indirections. The first pointer carries the location of the second pointer, which points to the address where the value of the real variable is kept.

An example of how to define a pointer to a pointer.

#include <iostream>
using namespace std;
 
int main()
{
    int a = 100;
    int *b = &a;
    int **c = &b;
    cout << "Value of variable a is " << a << endl;
    cout << "Address of variable a is " << b << endl;
    cout << "Address of pointer b is " << c << endl;
    return 0;
}

Output:

Value of variable a is 100

Address of variable a is 0x61feb8

Address of pointer b is 0x61feb4

Arrays and Pointers

Storing an array’s address into a pointer differs from storing a variable’s address into a pointer. The name of an array is the address of the array’s first index. As a result, using the (ampersand)& operator with the array name to assign an address to a pointer is incorrect. Instead, we used the array’s name.An example programme for saving the array’s initial address in the pointer,

#include <iostream>
using namespace std;
 
int main()
{
    int a = 10;
    cout << "Address of variable a is " << &a << endl;
    return 0;
}

Output:

The value of marks[0] is 99

We can utilise pointer arithmetic, such as addition and subtraction of pointers, to access other items of the same array that pointer p points to.

*(p+1) returns the value in the array’s second position. This is how it works:

int marks[] = {99, 100, 38};
int *p = marks;
cout << "The value of marks[0] is " << *p << endl;
cout << "The value of marks[1] is " << *(p + 1) << endl;
cout << "The value of marks[2] is " << *(p + 2) << endl;

output:

The value of marks[0] is 99
The value of marks[1] is 100
The value of marks[2] is 38

The post Operations on Pointers-Part II first appeared on Student Projects.

& is sometimes referred to as the Referencing Operator. It’s a one-of-a-kind operator. The variable name that is used in conjunction with the Address of operator must be the name of a previously declared variable.

Using the & operator with a variable returns the variable’s address number.

Here’s an example of how the operator’s address can be used.

#include <iostream>
using namespace std;
 
int main()
{
    int a = 10;
    cout << "Address of variable a is " << &a << endl;
    return 0;
}

Output:

0x61febc

The Indirection Operator

 * is also known as the Dereferencing Operator. It is a unary operator. It takes an address as an argument and returns the content/container whose address is the argument.

Here’s one example of how to utilise the indirection operator.

#include <iostream>
using namespace std;
 
int main()
{
    int a = 100;
    cout << "Value of variable a stored at address " << &a << " is " << (*(&a)) << endl;
    return 0;
}

Output

Value of variable a stored at address 0x61febc is 100

The post Operations on Pointers-Part I first appeared on Student Projects.

Here is an illustration of how to use the operator’s address.

#include <stdio.h> 
int main()
{
    int a = 100;
    printf("%d\n", a);
    printf("Address of variable a is %d", &a);
    return 0;
}

Output: 100

Address of variable a is 6422220

Operator for indirection (*):

The operator for indirection is *.Another name for it is the “Dereferencing Operator.”The operator is also unary.It uses an address as a justification.* returns the content or container whose argument is its argument’s address.

#include <stdio.h>
int main()
{
    int a = 100;
    printf("Value of variable a stored at address %d is %d.", &a, *(&a));
    return 0;
}

Output: Value of variable a stored at address 6422220 is 100.

The post Operations on Pointers first appeared on Student Projects.