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c++arrayslistconstructorinitialization

Initialization list for an array of objects that that take parameters C++


In C++ I am trying to initialize in my constructor an array of objects that their constructor takes one or more arguments. I want to do this on the initialization list of the constructor and not its body. Is this possible and how?

What I mean:

class A{
  public:
    A(int a){do something};
}

class B{
  private:
    A myA[N];
  public:
    B(int R): ???? {do something};
}

What should I put in the ??? to initialize the array myA with a parameter R?


Solution

  • If you have C++11, you can do:

    B(int R) : myA{1, 2, 3, 4, 5, 6} { /* do something */ }
    

    Although, if you are using Visual Studio 2013, please note that this syntax is currently NOT supported. There is the following workaround, however (which is arguably better style anyways):

    #include <array>
    
    class B {
        std::array<A, N> myA;
    
    public:
        B(int R) : myA({1, 2, 3, 4, 5, 6}) {}
    };
    

    Note, however, that N has to be a compile-time constant, and the number of initializers has to match the number of initializers.