Problem Statement

Idiomatically determine all the lowercase and uppercase letters   (of the Latin [English] alphabet)   being used currently by a computer programming language. The method should find the letters regardless of the hardware architecture that is being used (ASCII, EBCDIC, or other).

Display the set of all: that can be used (allowed) by the computer program, where   letter   is a member of the Latin (English) alphabet:     a ──► z     and     A ──► Z.

You may want to mention what hardware architecture is being used, and if applicable, the operating system.

Let's start with the solution:

void main() {
  String lowercase = '';
  for (var c = 0x61; c < 0x7b; c++) lowercase += String.fromCharCode(c);
  print(lowercase);

  String uppercase = '';
  for (var c = 0x41; c < 0x5b; c++) uppercase += String.fromCharCode(c);
  print(uppercase);
}