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

In how many different ways can we use concepts??

In how many different ways can we use concepts??

`std::integral<T> || std::floating_point<T>`

For the given typename `T`
 ```
template<typename T>
```
 which constraints are required such that `T` behaves like a number?

For the given typename <code>T</code>
<pre><code>template&lt;typename T&gt;
</code></pre>
which constraints are required such that <code>T</code> behaves like a number?

We use the `requires` clause________the template parameter list and the function definition.

We use the <code>requires</code> clause________the template parameter list and the function definition.

**(True or False)** `std::same_as`  takes two parameters and checks whether two types are the same or not.

(True or False) <code>std::same_as</code> takes two parameters and checks whether two types are the same or not.

What is the output of the following code?

```c++
template <typename T>
concept Number = std::integral<T> || std::floating_point<T>;

template <Number T>
T sub(T a, T b) {
 return a-b;
}
int main()
{
 std::cout<<sub(5, 3.5);
}
```

What is the output of the following code?
<pre><code class="language-c++">template &lt;typename T&gt;
concept Number = std::integral&lt;T&gt; || std::floating_point&lt;T&gt;;

template &lt;Number T&gt;
T sub(T a, T b) {
 return a-b;
}
int main()
{
 std::cout&lt;&lt;sub(5, 3.5);
}
</code></pre>

```c++
auto add(Number auto a, Number auto b)

```

```c++
template <Number T>
auto add(T a, T b)
 
```

```c++
template <typename T>
auto add(T a, T b) requires Number<T> 
```

If you had to use abbreviated function templates for the following code, what would be the parameters of the add function?

```c++
template <typename T>
concept Number = std::integral<T> || std::floating_point<T>;

auto add(...) {
 return a+b;
}

int main() {
 std::cout << add(1, 2.5) << '\n';
}

```

If you had to use abbreviated function templates for the following code, what would be the parameters of the add function?
<pre><code class="language-c++">template &lt;typename T&gt;
concept Number = std::integral&lt;T&gt; || std::floating_point&lt;T&gt;;

auto add(...) {
 return a+b;
}

int main() {
 std::cout &lt;&lt; add(1, 2.5) &lt;&lt; '\n';
}

</code></pre>

`requires` clause or the trailing `requires` clause

For a complex requirement to be able to use an expression, you need the ________ .

For a complex requirement to be able to use an expression, you need the ________ .

What is the best default way to use concepts?

What is the best default way to use concepts?

 **(True or False)** There are key differences in the code generated with the different ways to use concepts.

(True or False) There are key differences in the code generated with the different ways to use concepts.

Concepts with functions

Concepts with functions

Let’s test your knowledge of the different ways to use concepts 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 the Ways to Use the C++ Concepts