Can I call a constructor from another constructor (do constructor chaining) in C++?

Question

As a C# developer I\'m used to running through constructors:

class Test {
    public Test() {
        DoSomething();         


        

Answer 1

Simply put, you cannot before C++11.

C++11 introduces delegating constructors:

Delegating constructor

If the name of the class itself appears as class-or-identifier in the member initializer list, then the list must consist of that one member initializer only; such constructor is known as the delegating constructor, and the constructor selected by the only member of the initializer list is the target constructor

In this case, the target constructor is selected by overload resolution and executed first, then the control returns to the delegating constructor and its body is executed.

Delegating constructors cannot be recursive.

class Foo {
public: 
  Foo(char x, int y) {}
  Foo(int y) : Foo('a', y) {} // Foo(int) delegates to Foo(char,int)
};

Note that a delegating constructor is an all-or-nothing proposal; if a constructor delegates to another constructor, the calling constructor isn't allowed to have any other members in its initialization list. This makes sense if you think about initializing const/reference members once, and only once.