Initializing an array within a c++ constructor

Question

I want to have an array as a class member, but the only way I know how to initialize the array in the constructor is by adding each element individually (array[x] = char)

class MyClass
{
  public:
    MyClass();
    ~MyClass();
    void PrintLetters(); // Prints each character in the array
  private:
    int alpha[3]; // Allocate memory for array
};

MyClass::MyClass()
{
    // Initialize the array
    alpha[0] = 1;
    alpha[1] = 2;
    alpha[2] = 3;

    PrintLetters();
}

MyClass::~MyClass()
{
}

void MyClass::PrintLetters()
{
    for (int x = 0; x < 3; x += 1)
    {
        cout << alpha[x] << endl;
    }
}

int main()
{
    MyClass abc;

    return 0;
}

Is there another way to do it? If I try to do it like this:

MyClass::MyClass()
{
    // Initialize the array
    alpha[3] = {1, 2, 3};

    PrintLetters();
}

I get the following error: Expression syntax in turbo c++

score 4 · Accepted Answer · answered Jul 08 '15 at 12:26

4

I believe in GCC at least, with -std=c++11, you can do this:

MyClass::MyClass() : alpha{1, 2, 3}
{
    PrintLetters();
}

This is just an array initialization in the member initialization list. It's a standard C++ feature, but some compilers (cough VC++ cough) might not have implemented it yet.

answered Jul 08 '15 at 12:26

Sam Estep

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1

I confirm it still doesn't work with VC2013... – BlackDwarf Jul 08 '15 at 12:29
1

The [web compiler](http://webcompiler.cloudapp.net/) compiles it. So yes, it has been implemented. – chris Jul 08 '15 at 12:30
Works `std::array` in VC120, IIRC. – melak47 Jul 08 '15 at 12:31
`int alpha[3] = {1, 2, 3};` inside the class definition would also work, assuming c++11 support. – Michael Jul 08 '15 at 12:31
@Michael I'm relatively sure that *that*'s wasn't implemented in in VC140 last time I checked. – melak47 Jul 08 '15 at 12:32

Initializing an array within a c++ constructor

1 Answers1