Re: [Boost-users] [boost][array] Multi-dimensional initialization

Peter Dimov wrote:

Michael Marcin wrote:

...

<snip>

To initialize a boost::array "by the book" you need double braces:

boost::array foo = {{ 1, 2 }};

because a boost::array is essentially

struct array { int data[2]; };

and, according to the initializer rules, the outer braces are for the array struct, and the inner braces correspond to the data[] array.

In most cases you can drop the outer braces. In your last example, however, dropping them creates an ambiguity, and you need:

boost::array< boost::array, 4 > foo = {{ {-1,1}, {0,0}, {1,-1}, {2,-2} }};

Ahah. It makes sense now, thank you.