Array data type

Array data type

Can somebody help me with arrays. in fact I don't understand the
difference between these declarations:
Dim MyArray as integer()={5,3,2}
and
Dim MyArray() as integer={5,3,2}
and
Dim MyArray as array={5,3,2}
I have written a large code some variables are defined by the third
approach. Now I need to change the size of my array and add new elements
one by one to my array, but
array.resize(MyArray,newsize)
just works on arrays defined by the first and second method. How I can
change the size of array defined by the third method. How can I add
elements to this type of array one by one?
Thanks a lot