C tokens, Identifiers and Keywords are the basics in a C program. All are explained in this page with definition and simple example programs.
1. C TOKENS:
- C tokensare the basic buildings blocks in C language which are constructed together to write a C program.
- Each and every smallest individual units in a C program are known as C tokens.
C tokens are of six types. They are,
- Keywords (eg: int, while),
- Identifiers (eg: main, total),
- Constants (eg: 10, 20),
- Strings (eg: “total”, “hello”),
- Special symbols (eg: (), {}),
- Operators (eg: +, /,-,*)
C TOKENS EXAMPLE PROGRAM:
int main()
{
int x, y, total;
x = 10, y = 20;
total = x + y;
printf ("Total = %d \n", total);
}
where,
- main – identifier
- {,}, (,) – delimiter
- int – keyword
- x, y, total – identifier
- main, {, }, (, ), int, x, y, total – tokens
Do you know how to use C token in real time application programs? We have given simple real time application programs where C token is used. You can refer the below C programs to know how to use C token in real time program.
2. IDENTIFIERS IN C LANGUAGE:
- Each program elements in a C program are given a name called identifiers.
- Names given to identify Variables, functions and arrays are examples for identifiers. eg. x is a name given to integer variable in above program.
RULES FOR CONSTRUCTING IDENTIFIER NAME IN C:
- First character should be an alphabet or underscore.
- Succeeding characters might be digits or letter.
- Punctuation and special characters aren’t allowed except underscore.
- Identifiers should not be keywords.
3. KEYWORDS IN C LANGUAGE:
- Keywords are pre-defined words in a C compiler.
- Each keyword is meant to perform a specific function in a C program.
- Since keywords are referred names for compiler, they can’t be used as variable name.
C language supports 32 keywords which are given below. Click on each keywords below for detail description and example programs.
| auto | double |
| int | struct |
| const | float |
| short | unsigned |
| break | else |
| long | switch |
| continue | for |
| signed | void |
| case | enum |
| register | typedef |
| default | goto |
| sizeof | volatile |
| char | extern |
| return | union |
| do | if |
| static | while |
