Q.For what purpose character sets are used?

The character set of C is the complete collection of characters the language recognises. It is made up of letters (A-Z, a-z), digits (0-9), special characters (such as + - * / % = < > ( ) { } ; , . # &), and white-space characters (blank space, tab, newline). Every part of a C program is written using only these characters.

When these characters are grouped together according to the rules of C, they form tokens - the smallest individual units that the compiler treats as meaningful. C has six kinds of tokens:

1. Keywords - reserved words with a fixed meaning, such as int, if, while, return.
2. Identifiers - names given by the programmer to variables, functions and arrays.
3. Constants - fixed values such as 100 or 'A'.
4. Strings - sequences of characters enclosed in double quotes, e.g. "hello". …