C++ Concepts by Sándor Dargo_468 x 60 copy.png

clang-gcc.tar.gz

c++20

clang

This course will walk you through the newest version of C++ 20, C++ Concepts.

You will go through one of the most significant new features in C++20, which is Concepts. Concepts allow you to create compiler-checked criteria for template parameters, revolutionizing the way you think about and develop generic code. You can use them to provide both syntactic and semantic requirements. They also allow you to explicitly express your goal in the type system. If something goes wrong, you'll get a clear error message from the compiler.

While useful, Concepts can be difficult to apply and even confusing sometimes. This course provides you with the knowledge you need to overcome these obstacles and move on to more complex topics.

Let's get started.

C++ Concepts: Improve Type Safety with C++ 20

A template is used to manipulate classes.


A template is used to create generic functions and classes.

 Which below best describes the use case of a template?

Which below best describes the use case of a template?

What is the output of the following code?

```c++
template<typename T, typename U>
T max(T a, U b){
 return a < b ? b : a;
}
int main(){
 cout<<max(3, 4.5)<<endl;
 cout<<max('A', 97)<<endl;
 cout<<max(9.8, 8.9)<<endl; 
}

```

What is the output of the following code?
<pre><code class="language-c++">template&lt;typename T, typename U&gt;
T max(T a, U b){
 return a &lt; b ? b : a;
}
int main(){
 cout&lt;&lt;max(3, 4.5)&lt;&lt;endl;
 cout&lt;&lt;max('A', 97)&lt;&lt;endl;
 cout&lt;&lt;max(9.8, 8.9)&lt;&lt;endl; 
}

</code></pre>

What is the output of the following code?
```
template<typename T>
T increase(T a){
 return a+1;
}
template<>
char increase<char>(char a){
 return a-32;
}
int main(){
 cout<<increase(3.8)<<endl;
 cout<<increase('a')<<endl;
}
```

What is the output of the following code?
<pre><code>template&lt;typename T&gt;
T increase(T a){
 return a+1;
}
template&lt;&gt;
char increase&lt;char&gt;(char a){
 return a-32;
}
int main(){
 cout&lt;&lt;increase(3.8)&lt;&lt;endl;
 cout&lt;&lt;increase('a')&lt;&lt;endl;
}
</code></pre>

Validate template arguments at compile-time.


Provide a way to express the requirements for interfaces.

Validate the value of function arguments at runtime.

Remove the need for implicit conversions.

**(Select all that apply.)** What purpose(s) do concepts serve?


(Select all that apply.) What purpose(s) do concepts serve?

They constrain the types accepted by a template.


They document the constraints of a template at the top instead of hiding them in the body.

**(Select all that apply.)** What problem(s) do concepts solve that templates on their own cannot?


(Select all that apply.) What problem(s) do concepts solve that templates on their own cannot?

They might allow code to compile that was not intended

They might help us to compile all kinds of data types.

6. **(Select all that apply.)** What are the problems with implicit conversions?


<ol start="6">
<li>(Select all that apply.) What are the problems with implicit conversions?</li>
</ol>

Forbidding template specializations is not reusable.


We can’t use type traits for forbidding template specializations.

Why are concepts a better alternative than simply forbidding template specializations with `= delete`?


Why are concepts a better alternative than simply forbidding template specializations with <code>= delete</code>?

C++ templates 

C++ templates

Let’s test your knowledge of templates in C++.

Introduction

The Concept Behind C++ Concepts

Four Ways to use Concepts in Functions

C++ Concepts with Classes

Concepts Shipped with the C++ Standard Library

How to Write Your Own C++ Concepts

How to Use C++ Concepts in Real Life

Summary

Quiz on C++ Templates