☞It is a set of valid characters that a language can recognize. Examples:-
☞Letters:- A to Z, a to z
☞Digits:- 0 to 9
☞Special symbols:- + - * = [ ] { } == @ # etc
☞Whitespaces:- blank space, newline etc
☞It supports the Unicode coding standard.
A to Z ➺ 65 to 90
a to z ➺ 97 to 122
0 to 9 ➺ 48 to 57