Difference between Keyword and Identifier
Difference between Keyword and Identifier

Developers must understand programming language concepts and terms to be successful. When using C programming, it’s important to know the difference between keyword and identifier. This article explains two crucial aspects of C programming and their distinctions.

What is the difference between keyword and identifier

In the realm of programming languages, keywords, and identifiers play distinct roles. Writing code requires both, but they have different purposes and characteristics. Let’s delve deeper into each of these components and unravel their dissimilarities.

What is a Keyword?

In a programming language, reserved words called keywords hold predefined meanings. Symbols are important for the structure of language. But, you can’t use them as names for things or variables. Like other programming languages, C has keywords that do specific tasks or operations.

C programmers utilize terms known as keywords to define the functionality of their program. These keywords serve to describe the information utilized by the program as other components of the programming language. In C keywords such as “if,” “for,” and “while” are employed to control decision making and looping processes. Additionally programmers make use of keywords like “int ” “float,”. Char” to establish data types.

Programmers cannot redefine or change keywords, as they have special significance. The compiler treats them based on their purpose in the language. To make the code work , it’s important to follow the rules for using keywords.

What is an Identifier?

Programmers give program elements like variables and functions user-defined names, called identifiers. Programmers can choose identifiers based on their preferences, unlike reserved words called keywords. The names help us understand what the program elements are for.

Identifiers in C are made up of letters, numbers, and underscore. However, they have to commence with a letter or underscore. These commands comprise letters that have a different version for capitalization hence being case-sensitive. The selection of relevant and descriptive aliases improves the codability and supportability of software.

Identifiers play a role, in establishing connections between sections of a program. Programmers rely on them to declare variables, define functions and create custom data types. Opting for a chosen name can greatly enhance the comprehensibility of the code, for all individuals involved.

Keyword Vs Identifier: Explore the difference between Keyword and Identifier

In C programming, keywords and identifiers are important. They have different purposes and characteristics. The following points highlight the key difference between keyword and identifier:

DefinitionReserved words with predefined meaning in CUser-defined names used to represent various entities
UsageHave specific purposes and functionalitiesRepresent variables, functions, and other entities
AlterabilityCannot be redefined or used for any other purposeCan be freely chosen by the programmer
Examplesint, float, if, else, for, while, return, etc.Variable names, function names, labels, etc.
PurposeServe as building blocks of the C programming languageProvide a means for the programmer to create their own symbols for various entities
RestrictionsCannot be used for any other purpose or redefinedShould follow C naming conventions and rules
Predefined NumberLimited and fixed numberUnlimited and can be created as needed

Also Read : Difference between Array and Pointer

Keyword Characteristics

  • Keywords are pre-defined and reserved by the C language.

  • The codes have assigned meanings that help establish their syntax and logic.

  • The compiler only uses keywords, so you can’t use them as identifiers or variable names.

  • Examples of keywords in C include if, else, while, for, int, and return.

Identifier Characteristics

  • Programmers assign identifiers to denote variables, functions, or user-defined elements.

  • They provide unique names to refer to specific memory locations within the program.

  • Identifiers make code easier to read and understand by showing what elements do and why.

  • In the C programming language you must start identifiers with either a letter or an underscore. These identifiers can contain letters, digits and underscores.

  • Identifiers in C can be of any length, but only the first 31 characters are significant. This limitation should be considered when naming identifiers to ensure uniqueness and avoid any potential confusion.

  • Examples of identifiers in C include count, variable_name, and calculate_area.

Keywords and identifiers are important in C programming, but they have different roles. In structured programming, predefined instructions are keywords. Identifiers are user-defined labels that enhance code readability and help efficient data manipulation.

Frequently Asked Questions

Q: What is the main difference between keyword and identifier in C?

A: In the C programming language a keyword is a word that already has a meaning. Examples of keywords include “if ,” “else,” and “While.” On the other hand an identifier is a name created by the programmer, for elements in their program, like variables, functions or arrays.

Q: What is the difference between keywords and identifiers in Verilog?

A: In Verilog reserved words known as keywords have predefined meanings. Cannot be utilized as identifiers. On the side identifiers are names specifically chosen by users to refer to variables, modules or any other user defined constructs. They play a role in identifying and referencing various elements within the code.

Q: What is the difference between keyword and variable?

A: A keyword refers to a word, with a predefined significance, in a programming language. It cannot be employed as an identifier like a name.
On the contrary a variable is a name that represents data stored in the memory of the computer. It can be assigned values while a program runs.

Q: What is an identifier example?

A: An identifier is a name given to a variable in a computer program, such as “myVariable” or “studentID.”

Q: What is the keyword with an example?

A: keywords are the reserved word that has a meaning and cannot be utilized as an identifier. For example, “int” is a keyword used for declaring integer variables.

Q: Can identifiers be the same as keywords in C?

A: No, identifiers cannot be the same as keywords in C.

Q: Are keywords case-sensitive in C?

A: Yes, keywords are case-sensitive in C.


In the programming language C it is important for programmers to have an understanding of the distinction, between keyword and identifier. This knowledge is essential not for writing code that’s easy to read but also for ensuring that your C programming is free, from errors and runs efficiently.

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