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c++classinitialization

Initializing a member variable with parameters in c++

I have a class Foo with the ONLY constructer Foo(int length). I also have a class ´Bar´ with the member Foo myFoo = myFoo(100) how would I initialize that? I can only initialize it if it has no length parameter in Foo constructer.

Thanks in advance

Solution

  • I'm not sure if I understood you correctly, but normally members are initialized in constructor initializer lists:

    class Bar
{
public:
  Bar(); 
private:
  Foo myFoo;
};

Bar::Bar()
// The following initializes myFoo
  : myFoo(100)
// constructor body
{
}

    Note that if Bar has several constructors, you have to initialize myFoo in each of them.

    C++11 added initialization directly in the member declaration, like this:

    class Bar
{
  Foo myFoo = Foo(100);
};

    However your compiler might not support that yet, or only support it with special flags.