Character set and C-Tokens

Character Set: C is a powerful programming language. Not only C, every language follows some rules. These rules are required for writing a program. In order to write a program some alphabets, digits and special symbols are used. All this is known as Character set. Character set is used to write program blocks, variables and identifiers etc. Character set consists of the upper and lower case alphabets, digits, special characters and white space.

Alphabets: It consists of both upper and lower case alphabets. It can be ‘A’ to ‘Z’ or ‘a’ to ‘z’ or combination of the alphabets. These are used for naming purpose. C language is a case sensitive language. It means that lower and upper case alphabets are different. For example: 'A' is different from 'a'. Both can be used in the program and both can contain different values. But one thing should be noted that same variable or name cannot be used for two purposes. If we do so then it will create a big confusion.

Digits: Digits represent to the numeric values. These are used by the programmer for assigning the values to the variables. Digits are same as the mathematical digits i.e. 0 to 9 or combination of the digits. It consists both of positive and negative numbers. Also it includes decimal point values. The programmer can assign any numeric value depending on the data type. For example: a=5, b=109, c=-69, d=48.56

Special Symbols: On the keyboard all keys are special symbols except alphabets, digits and function keys or hot keys. Such as: &, $, @. All these symbols are used for special purposes.

Tokens: Tokens are various C program elements. Tokens are identified by the compiler during compilation. Tokens are useful for compiler to detect errors. When tokens are not arranged in a particular sequence then compiler generates an error message. These tokens are: Keywords, Identifiers, Variables, Constants and Delimiters or separators