Since we are working with 0's and 1's only, to represent character in computer we use strings of 0's and 1's only.
To represent character we are using some coding scheme, which is nothing but a mapping function.
Some of standard coding schemes are: ASCII, EBCDIC, UNICODE.
ASCII : American Standard Code for Information Interchange.
It uses a 7-bit code. All together we have 128 combinations of 7 bits and we can represent 128 character.
As for example 65 = 1000001 represents character 'A'.
EBCDIC : Extended Binary Coded Decimal Interchange Code.
It uses 8-bit code and we can represent 256 character.
UNICODE : It is used to capture most of the languages of the world. It uses 16-bit
Unicode provides a unique number for every character, no matter what the platform, no matter what the program, no matter what the language. The Unicode Standard has been adopted by such industry leaders as Apple, HP, IBM, JustSystem, Microsoft, Oracle, SAP, Sun, Sybase, Unisys and many others.