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

# When is `const` ignored?

In the section about const functions, we saw that the following signatures are declared two different overloads.

We can overload a function based on its constness.

#include <iostream>

class A {
 public:
    void foo(){
        std:: cout<<"Non const"<< '\n';
    }
  
    void foo() const{
        std:: cout<<"const"<< '\n';
    }
};

int main() {
    A a;
    a.foo();
}

On the other hand, any `const` qualifier on a non-reference type parameter or on a return type doesn’t create a new overload. As a result, the following code will fail to compile.

We cannot overload functions based on non-reference type parameters’ constness.


Introduction

Arguments using const

Local Variables

Local Members

Functions

Return Types

const Parameters

const and Smart Pointers

Rvalue References

Summary

Ignoring the const

When is `const` ignored?

Ignoring the const

When is const ignored?

When is `const` ignored?