C Identifiers

An identifier is a sequence of characters that consists of alphabets, digits, and an underscore character. It should start with either an alphabet or an underscore character. It cannot include spaces, punctuation marks, or special characters.

Example

#include <stdio.h>

int main() {
   int num = 10;
   printf("Value of num is %d", num);
   
   return 0;
}

Explanation

In the above example, num is an identifier used to declare and store a variable of type integer. It represents the name of the variable and is identifiable by the compiler for further usage in the program.

Use

Identifiers are used to name variables, functions, and user-defined data structures in the C language. They provide a unique name to an entity, making it easier to refer to it in the code. The following are some derivative uses of identifiers:

• Identifiers help to improve the readability of your code by giving meaningful names to variables and functions.
• Identifiers help to make code more reusable, as the same identifier can be used in a different code context, giving the same variable or function a more significant reference.

Important Points

• Identifiers are case-sensitive, which means that num, Num, and NUM are all different identifiers.
• C language reserves certain keywords or pre-defined identifiers that cannot be used as identifiers, such as if, else, while, etc.
• Identifiers must not exceed more than 31 characters in length in the C language.
• The first character of an identifier should either be an alphabet or an underscore character.

Summary

Identifiers play an essential role in C language programming as they are used to name variables, functions, and user-defined data structures within the language. Identifiers help to improve the readability of your code, and they allow you to easily refer to an entity within your program. Understanding the syntax and rules for identifiers is a fundamental aspect of C programming, and it is crucial to ensure that your code is well-organized and easy to read.