All 4 of these Powershell lines do exactly the same thing. Load the first 256 chars into a char array.
for ([int]$i = 0; $i -le 255; $i++) {$a += [char]$i};
0..255|%{$a+=[char]$_}
$a=0..255|%{[char]$_}
[char[]]$a=0..255