Gain insights into the C++ keyword 'const,' its usage in various contexts, and implications when returning pointers and references. Learn about preventing accidental data changes.

How to use const in C++ by Sándor Dargo_468 x 60 copy.png

In this course, you will learn about the C++ keyword const and its behaviour under different usage conditions, including local, global and static contexts. This course will help you to understand const and its implications when you attempt to return pointers and references in C++. By the end of the course, you will have a solid grip on const and its usage in preventing any accidental change of data.

Secure Coding Practices in C++: A Deep Dive into const

The `const` keyword specifies that a value is "constant" and cannot be changed after it's initially set. This is useful because it can reduce the complexity of our program by reducing how many elements can change in the program environment. However, we also have to be careful when using `const` variables because we cannot reverse our `const` specification.

If we can make something const, we should make it `const`. That is the least we can do for our compiler. 

Many senior C++ developers give the above advice to junior developers, but often fail to follow it themselves!

It is very easy to declare a variable without making it `const`, we know that its value should never change. However, our compiler doesn’t know that.

The compiler cannot think, after all, at least not for the time being.

Compilation errors are easy to spot early on, but dangling references or degrading performance due to extra copies may be more difficult to identify.

Hopefully, those are caught no later than [the code review](https://www.sandordargo.com/blog/2018/03/28/codereview-guidelines ) stage.



## How to use the `const` keyword
In this course, you will learn how to use the `const` keyword in different contexts, such as:



* `const` functions
* `const` local variables
* `const` member variables
* `const` return types
* `const` parameters
* `const` and smart pointers
* Rvalue references



Although the keywords `constexpr`, `consteval`, and `constinit` are related to `const`, we will not discuss those in this course.



# How to use the `const` keyword
In this course, you will learn how to use the `const` keyword in different contexts, such as:



A brief introduction of the 'const'  keyword and how it can be used.

Introduction

Arguments using const

Local Variables

Local Members

Functions

Return Types

const Parameters

const and Smart Pointers

Rvalue References

Summary

A Bit about const

How to use the `const` keyword