2. What is Identifiers
A C identifier refers to name used to identify a variable, function, structures or any
other user-defined item or entity.
Identifier must be unique. They are created to give unique name to a
entity/item/variable name to identify it during the execution of the program
identifier names must be different from keywords. Because Keywords are
predefined, reserved words used in programming .As for Example :You cannot
use double as an identifier because double is a keyword.
3. Identifiers Example
int roll_no;
double percentge_marks;
float average;
Here, roll_no , percentge_marks , average are identifiers.
Here are some another examples of acceptable identifiers
zakir Ram abc movie_name ab_123
myname50 _temp p a666b9 sum avg multi
4. Rules for writing an identifier
The first letter of an identifier should be either a letter or an underscore.
A valid identifier can have letters (both uppercase and lowercase letters), digits
and underscores.
There is no rule on length of an identifier. However, the first 31 characters of
identifiers are significant by the compiler.
Must not contain white space
Can not use Keyword as a identifier
5. identifiers in Programming
#include<stdio.h>
int main () {
/* variable definition: */
int variable_1, variable_2;
int variable_3;
variable_1=6;
variable_2=6;
variable_3 = variable_1 + variable_2;
printf("value of c : %d n", variable_3 );
return 0;
}
In this Example identifiers are:
variable_1
variable_2
variable_3
OutPut
value of c : 12
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