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

Returning `const` values decreases the efficiency and can’t store in a variable.

Returning `const` values prevents the application from moving semantics and you might end up with a silent copy instead.

How can returning const values from a function hurt performance?


How can returning const values from a function hurt performance?

A reference/pointer that points to the wrong memory location.


A reference/pointer that points to an object that has been already destroyed.

A reference/pointer that is not initialized.

What is a dangling reference/pointer?

When the pointer doesn’t become dangling.

If the returned object is guaranteed to stay alive at least as long as the caller object.

In what situation is it safe to return a (`const`) pointer or reference?


In what situation is it safe to return a (<code>const</code>) pointer or reference?

Accuracy. The thing on the left of `const` is more accurate.


Consistency. The thing on the left of `const` is always `const`.

What is the advantage of *east `const`* over *west `const`*? 

What is the advantage of east <code>const</code> over west <code>const</code>?

The object the pointer points to can be modified because it’s mutable.


The pointer can be modified as type qualifiers are ignored on function return types.

The `const` pointer can only return to an immutable object.


Which of the following occurs when you return a `const` pointer to a mutable object? Select all that apply.

Which of the following occurs when you return a <code>const</code> pointer to a mutable object? Select all that apply.

The object the pointer points to cannot be modified as it’s `const`.

Returning a mutable pointer can change the value of the variable.

What happens when you return a mutable pointer to a `const` object?

What happens when you return a mutable pointer to a <code>const</code> object?

Here's a short quiz to test your understanding.

Introduction

Arguments using const

Local Variables

Local Members

Functions

Return Types

const Parameters

const and Smart Pointers

Rvalue References

Summary

Quiz