C++ Introduction to pointers

A pointer is a C++ term for a variable that keeps track of another variable’s memory address. Dynamic memory allocation and memory management are made possible through pointers, which give users a direct mechanism to manipulate and access data in memory.

An asterisk (*), also known as the dereference operator, must be given after the type of the variable a pointer points to in order to declare one.

Syntax of pointer:

data_type *pointer_name;

Example of declaring pointer:

int* ptr;

This declares an integer variable named ptr as a pointer. The memory location of a variable can be obtained using the & operator and then allocated to a pointer:

int num = 5;
int* ptr = &num;

The & operator is used in this example to acquire the address of the variable num and assign it to the pointer ptr. The dereference operator (*) can be used to indirectly retrieve the value of the variable num:

cout << "Value of num: " << *ptr << endl;

This will display the variable num’s value, which is 5.

The new operator, which allocates memory on the heap, can alternatively be used to allocate dynamic memory via pointers:

int* ptr = new int;

This allocates the necessary space in memory to hold an integer variable and then gives back a reference to the memory block’s first byte. The delete operator can be used to deallocate the memory:

delete ptr;

Functions can take pointers as parameters, which gives the function the ability to change the data that the pointer points to. Moreover, they can be utilised to build more complex data structures like binary trees and linked lists. Pointers can cause memory leaks, segmentation faults, and other issues, though, if they are not utilised appropriately. Pointers should only be used sparingly and with an understanding of how they operate.