CODEWITHSUNDEEP
c++arraysclassconstructorinitializer-list
Akiiino
Akiiino

Reputation: 1090

Initializer list to array

As of now, I have a class Permutation, which has this:

public:
 int elements[N];
 Permutation(std::initializer_list<size_t> data): elements(data) {};

But when I try to compile, I get this:

error: array initializer must be an initializer list

I've googled the hell out of the initialiser lists, though there is nothing that was useful/I could understand. So I do not have the tiniest idea about how to use the initialiser lists.

How do I write this constructor?

UPDATE

I also have this version:

public:
 int elements[N];
 Permutation(std::initializer_list<size_t> data): elements(new int[N]) {
     std::copy(data.begin(), data.end(), elements.begin(), elements.end());
 }

I'm pretty sure it's even more wrong, but if it's fixable, could someone tell me how to do this?

Upvotes: 3

Views: 2011

Answers (1)

R Sahu
R Sahu

Reputation: 206567

The second approach is close. It needs minor adjustments.

Permutation(std::initializer_list<int> data) : elements{}
{
   size_t size = data.size();
   if ( size <= N )
   {
      std::copy(data.begin(), data.end(), std::begin(elements));
   }
   else
   {
      std::copy(data.begin(), data.begin()+N, std::begin(elements));
   }
}

Upvotes: 2

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