Class construction with initial values

Question

I\'m new to C++, and the whole idea of classes - I\'m still reading a book to try and learn. The book I\'m reading says that when I construct a class, I can assign default v

Answer 1

The difference is that the compiler will always initialize all members (in declaration order) prior to the first user-defined constructor statement. In the case of a char and an int, which are both primitive types, 'initialization' actually means 'no initialization' here. However, if you have a member with a constructor that does some actual work, this constructor will be called upfront - if you do

foo::foo() {
    myComplexMember = MyComplexClass(42);
}

the compiler did already invoke the MyComplexClass default constructor before your code got called, which is a waste of resources (and a compiler error if the default ctor is not accessible).

By using an initialization list, you can customize the default initialization and avoid doing things for nothing. Obviously, this is the way to go.