How to Initialize Data Members in C++ From C++11 untill C++20.png

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Throughout this course, you will learn all the options to initialize data members in C++ using a simpler syntax and safer code. More specifically, in this mini course you will learn non-static data member initialization, inline variables, designated initializers, and more. Additionally, you’ll see the changes and new techniques from C++11 to C++20 to really round out your understanding.

Initializing Data Members: From C++11 till C++20

Non-static data member initialization has been available since which C++ standard?

Non-static data member initialization has been available since which C++ standard?

Can you use `auto` type deduction for non-static data members?

Can you use <code>auto</code> type deduction for non-static data members?

No, the declaration and definition can happen in the same place where a static member is declared.

Do you need to define a static inline data member in a separate `cpp` file?

Do you need to define a static inline data member in a separate <code>cpp</code> file?

Can a static inline variable be non-constant?

Can a static inline variable be non-constant?

See the following code:

```cpp
struct S {
 int a { 10 };
 int b { 42 };
};
```

What's the output of the following line?

```cpp
S s { 1 };
std::cout << s.a << ", " << s.b;
```

See the following code:
<pre><code class="language-cpp">struct S {
 int a { 10 };
 int b { 42 };
};
</code></pre>
What’s the output of the following line?
<pre><code class="language-cpp">S s { 1 };
std::cout &lt;&lt; s.a &lt;&lt; &quot;, &quot; &lt;&lt; s.b;
</code></pre>

`C::a` is initialized twice. The first time, it is initialized with `10` and the second time with `0` in the constructor.

`C::a` is initialized only once with 0 in the constructor.

The code doesn't compile because the compiler cannot decide how to initialize `C::a` member.

See the following code:

```cpp
class C {
    C(int x) : a(x) { }

    int a { 10 };
    int b { 42 };
};

C c(0);
```

Select the `true` statement:

See the following code:
<pre><code class="language-cpp">class C {
 C(int x) : a(x) { }

 int a { 10 };
 int b { 42 };
};

C c(0);
</code></pre>
Select the <code>true</code> statement:

What happens when you compile this code?

```cpp
class Point { int x; int y; };

Point pt {.y = 10, .x = 11 };
std::cout << pt.x << ", " << pt.y;
```

Select the `true` statement:

What happens when you compile this code?
<pre><code class="language-cpp">class Point { int x; int y; };

Point pt {.y = 10, .x = 11 };
std::cout &lt;&lt; pt.x &lt;&lt; &quot;, &quot; &lt;&lt; pt.y;
</code></pre>
Select the <code>true</code> statement:

Check your knowledge from this mini-course!

Check your knowledge from this mini-course!

Assess what you’ve learned from this mini course.

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✏️ The Final Quiz