C++ Pointers

In this lesson, we would learn about C++ pointers. This is one of the few topics that is distinguishes C++ from many other programming languages. So, it’s important you understand it.

1. Overview of C++ Pointers
2. Creating Pointers
3. Using Pointers in C++
4. Some Pointer Concepts

1. Overview of C++ Pointers

Pointers in C++ are variables that store memory address of other variables. So if you have a variable x, then to get its memory address, you use &x. The code below displays address of three variables

// Printing memory addresses of variables
int main () {
    // declare some variables
    int x = 67;
    string name = "Kindson";
    double y = 54.32;

    // print address of x
    cout << "Address of x: "<< &x << endl;

    // print address of name
    cout << "Address of name: " << &name << endl;

    // print address of y
    cout << "Address of y: " << &y << endl;

    return 0;
}

The output of the program is:

Address of x: 0x62fe08
Address of name: 0x62fde0
Address of y: 0x62fdd8

As you can see, the addressed are shown in hexadecimal (begins with 0x)

2. Creating Pointers

Similar to normal variables, you also need to declare a pointer before you can use it. However, pointer names are preceded by an asterisk(*). For example

int *myPointer; //pointer to int

int* myPointer; //pointer to int

int* myPointer, myVar; //a pointer and an int

The three lines above are all valid ways to declare a pointer. The first and second lines declares a pointer myPointer which is a pointer to an int variable. Third line declares a pointer myPointer and a normal variable myVar.

3. Using Pointers in C++

Let’s now create a pointer and assign the address of a variable to it.

// Working with point
int main () {
    // declare a variables, x
	int x = 34;

	// declare a pointer px
	int *px;

	// assign the pointer a value
	px = &x;

	// display the pointer value
	cout<<"Variable x " << x << " is stored at " << px;

    return 0;
}

The output is:

Variable x 34 is stored at 0x62fe14

Moreover, if you have a pointer and you want to know what value is stored there, you just also use *. The code below would get the value stored in px.

cout<<"Value stored in " << px << " is " << *px;

4. Some Pointer Concepts

There are a few concepts on pointers I would like to mention here finally.