multi_array, resize and default constructable
Dear all, from the documentation I read that if a multi_array is reshaped new elements are default constructed: "Resizing an Array The boost::multi_array class provides an element-preserving resize operation. ...Any new elements in the array are default constructed..." It is thus not possible providing a default fill element?
gast128 wrote:
Dear all,
from the documentation I read that if a multi_array is reshaped new elements are default constructed:
"Resizing an Array The boost::multi_array class provides an element-preserving resize operation. ...Any new elements in the array are default constructed..."
It is thus not possible providing a default fill element?
The default fill element is the default value of the type. For example, if you have a multi_array of doubles, on array construction (or resize) all new elements will be 0.0. You cannot change this value without changing the default value of the underlying type. Johann
Dr Johann A. Briffa <j.briffa <at> ieee.org> writes:
...Any new elements in the array are default constructed..."
It is thus not possible providing a default fill element?
The default fill element is the default value of the type. For example, if you have a multi_array of doubles, on array construction (or resize) all new elements will be 0.0. You cannot change this value without changing the default value of the underlying type. Johann
I understand that, built in types are also defined for default construction. However I had a need here to override that default. Looking at the vector::resize(), it offers an overload function for specifying the fill element. The case I needed was soemthing likea std::pair<HANDLE, nstring>, where the the default handle is -1 (i.e. std::pair<HANDLE, nstring> default(-1, ""));. Of course this can be solved by promoting this to a full blown struct with default ctor, but I donot like to introduce extra structures for just bundling data.
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Dr Johann A. Briffa -
gast128