Identifiers in C:-
Identifiers refer to the name of a variable, function and arrays. C Identifiers are names given to different entities such as constants, variables, structures, functions, etc.
Examples :-
int amount; double totalbalance;
In the above example, amount and totalbalance are identifiers, and int and double are keywords.
Rules for Identifiers:-
- First Character must be an alphabet (or underscore).
- must consist of only letters, digits, or underscore.
- It should be up to 31 characters long.
- Cannot use a keyword.
- must not contain white space.
- Identifier names must be unique.
- Identifiers are case-sensitive.
Types of Identifier in C:-
There are two types of Identifier in c.
- Internal Identifier
- External Identifier
1. Internal Identifier:- Identifiers which are used as a local variable or are not used in external linkage are called internal identifiers.
2. External identifier: Identifiers which are used as a global variable or used for naming function or any other external linkage are called external identifiers.
Keywords in C:-
Keywords are generally called as pre-defined or reserved words in a programming language. Every keyword in C language performs a specific function in a program.
Facts about Keyword :
- Keywords cannot be used as variable names.
- Keywords have fixed meanings, and that meaning cannot be changed.
- They are the building block of a ‘C’ program.
- C supports 32 keywords.
- All the keywords are written in lowercase letters.
The different types of keywords are as follows −
Examples :-
#include<stdio.h>
int main()
{
float a, b;
printf("Showing how keywords are used.");
return 0;
}In the above program, float and return are keywords. The float keyword is used to declare variables, and the return is used to return an integer type value in this program.
