Description
A program is nothing but a set of instructions which means words and symbols. These instructions are following certain rules called as Syntax Rules. C Syntax rules specify the sequence of characters, vocabulary and grammar in the program.
In C-Language, characters are divided into the following categories:
Character categories
- Letters (all alphabets a to z & A to Z).
- Digits (all digits 0 to 9).
- Special characters such as colon (:) , semicolon (;), period (.), underscore (_), ampersand (&) etc.
- White spaces.
- Every statement in C-program should end with a semicolon.
- White spaces are taken into consideration when keywords and identifiers are used.
- C is a case sensitive. So all the instructions should be given in lower case.
Description
C-tokens are the basic building blocks and smallest individual unit in writing a C-program. Tokens come together to form a program. They are divided into 6 types.
Token Types
Example
[c]
#include<stdio.h>
int main()
{
int x, y, total;
x=1, y=2;
total =x+y;
printf(“total=%d",total);
}
[/c]
Description
Keywords are those words whose meaning is already defined by Compiler i.e. include, int, main.
- Keywords are pre-defined words in C-Language.
- Keywords and variable names are not same, as keywords are already reserved in the compiler.
- Every keyword has its own meaning and cannot be edited by the programmer.
Keywords
| auto | break | long | return | double | else |
| enum | union | int | register | switch | do |
| short | case | continue | if | const | typedef |
| for | static | float | default | volatile | char |
| short | goto | auto | sizeof | extern | unsigned |
| signed | void | while |
Description
Identifiers refers to the names of variable, types, functions, labels and arrays. Unlike Keywords, Identifiers are user-defined and can be changed as per the requirement.
- First character of the identifier should be an alphabet(A-Z or a-z) or underscore( _ )
- First character should never be a digit or any other symbol except underscore.
- Identifiers are also case-sensitive.
Key Points
C syntax chapter draws out following main points.
- C-language is case sensitive.
- 32 Keywords in C-language which are pre-defined.
- Identifiers are user-defined.
Programming
Tips
Never use keyword as a variable name or function name as they are inbuilt in the system.