Member Initializer Lists | C++ Tutorial

A comprehensive explanation of how, when and why to use member initializer lists in C++, including:

- using member initializer lists with parameters, expressions and function calls

- improving performance by initializing object member variables that have both a default and parameterized constructors

- the difference between () and {} bracket styles in member initializer lists

- initializing reference member variables using member initializer lists

- initializing const member variables using member initializer lists

- initializing object member variables that only have parameterized constructor(s) and no default constructor, using member initializer lists

- creating a constructor for a derived class of a base class that has only parameterized constructor(s) and no default constructor, using member initializer lists

[ieduardoms]

Very useful. All the things you have explained in this video are very important to keep in mind. Thank you so much.

[Klusio]

I have a question. In 3:46 You said, that we have to follow the same order when initializing member list as the member variables were declared in the class. As with most things, I went and check that out. But I couldn't find any diffrence when initialazing in order or not. In both ways it worked. Take a look at my example class:

class TestClass{
public:
int number;
string name;

TestClass(string name_set, int number_set) : name(name_set), number(number_set)
{
cout << "Constructor executed!" << endl;
}
};

And it compiled and worked when I first did "TestClass(string name_set, int number_set) : name(name_set), number(number_set)"
and it worked the same when doing it "in order" : "TestClass(string name_set, int number_set) : number(number_set), name(name_set)"

Am I missing something? Or maby it depends on the language standard? (I checked on c++ 14 and c++23 and in both worked as I described). Or is it something else?

[SIVAJI_]

7:24 So, the Major class has two constructors, the constructor is invoked based arguments we passed, then its compile time polymorphism i.e function overloading, Am I right?

[jaishreejain]

Amazing😀
.Very helpful
Thank you Sir

[itsmaxim]

21:10 just pointing out that long int (which is the same as long) is the exact same 4 bytes on x64 systems, which are almost every system nowadays. On such systems long and int are identical, therefore there will be no type-narrowing.

[yuwownly]

I'm just wondering. What is the difference between major(Major(major)) and major(major) as the member initializer list?

[shafayet]

What will happen if I don't add Major(the class name) in major{Major{major}}