☞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 which includes the ASCII codes.
Unicode Universal Code(0 to 65535 = 65536 characters) It uses 16-bits code for representing each character. It represents character in hexadecimal digits ranging from 0x0000 upto 0xFFFF. ASCII code American Standard Code for Information Interchange(0 to 255 = 256 characters) It uses 7 bits code for representing each character. Only 128 characters(0 to 127) are used while designing and executing a program.
A to Z ➺ 65 to 90
a to z ➺ 97 to 122
0 to 9 ➺ 48 to 57
blank ➺ 32