To expand on bearophile's answer, a dynamic array is basically a
package of two things: a length and a pointer to the contents.
Each of these is 8 bytes on a 64-bit system, thus the sizeof a
dynamic array is 16 bytes.
You are asking how char, wchar, and dchar correspond to integer
types. That is defined here: http://dlang.org/type.html.
char = 1 byte (ubyte)
wchar = 2 bytes (ushort)
dchar = 4 bytes (uint)
To show this, print the sizeof an element in each of those arrays:
writeln( typeid( t ), ' ', t[0].sizeof, ' ',
t.representation() ); // 1
writeln( typeid( c ), ' ', c[0].sizeof, ' ',
c.representation() ); // 1
writeln( typeid( dc ), ' ', dc[0].sizeof, ' ',
dc.representation() ); // 4
writeln( typeid( wc ), ' ', wc[0].sizeof, ' ',
wc.representation() ); // 2
