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.

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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

# Introduction to `const` local variables
We can declare all our local variables that are not supposed to change their values as `const`. Doing so can help future readers of the code (including ourselves) and the compiler perform some optimizations.

## Local vs. global variables
```
auto mutableNumber{42};
mutableNumber = 666; // This is OK
const auto immutableNumber{42};
immutableNumber = 666; //error: assignment of read-only variable 'immutableNumber'
```
As mentioned previously, if we declare a local variable as `const`, we simply declare it as immutable. It can never change its value. If we try to modify it later on, we’ll get this compilation error: `you cannot assign to a read-only variable`.

Making an object immutable by default and using `const` for any object that has not and  will not change after its construction is the recommended practice.

Making global variables immutable is rather useful, because otherwise, anyone can modify their values. However, many developers choose to avoid global constants because they can introduce unnecessary coupling between components. 


Introduction

Arguments using const

Local Variables

Local Members

Functions

Return Types

const Parameters

const and Smart Pointers

Rvalue References

Summary

const Local Variables

Introduction to `const` local variables

Local vs. global variables

const Local Variables

Introduction to const local variables

Local vs. global variables

Introduction to `const` local variables