Comments on: 10.1 — Constructor initialization lists

By: Daniel

Daniel — Thu, 12 Jun 2008 00:41:35 +0000

Thanks, Daniel

By: Alex

Alex — Tue, 10 Jun 2008 02:52:19 +0000

Unfortunately, neither of those work. This actually hits on one of the shortcomings of the C++ language — there is no way to initialize non-static array members in C++.

However, there is a reasonable workaround. Because this is a constant array, we know the value of the members will never change — so why even have one array per class object? It makes more sense to define m_nValue as a static member, so it will be shared by all class objects. That way they all reference the same one and you save memory. And there IS syntax to initialize static array members in C++:

class Something
{
private:
    static const int m_nValue[3];
public:
    Something()
    {
    }
};

const int Something::m_nValue[] = {5, 6, 7}

By: Daniel

Daniel — Thu, 05 Jun 2008 00:20:21 +0000

Hi Alex, Just a question, can you use initialisation lists with arrays of members? something like this:

class Something
{
private:
    const int m_nValue[3];
public:
    Something(): m_nValue(5, 6, 7)
    {
    }
};

Or do you have to do it like this:

class Something
{
private:
    const int m_nValue[3];
public:
    Something(): m_nValue[0](5), m_nValue[1](6), m_nValue[2](7)
    {
    }
};

Thanks, Daniel

By: Learn C++ - » 9.12 — Shallow vs. deep copying

Learn C++ - » 9.12 — Shallow vs. deep copying — Mon, 05 May 2008 02:12:04 +0000

[...] 10.1 â€” Constructor initialization lists [...]

By: Learn C++ - » 10.2 -- Composition

Learn C++ - » 10.2 -- Composition — Tue, 04 Dec 2007 22:55:06 +0000

[...] the previous lesson on initializer lists, you learned that the preferred way to initialize class members is through initializer lists rather [...]