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Introduction
Every programming language has Keywords and Identifiers, which are only understood by its compiler. Identifiers and Keywords in the C Language are the building block of any program. An Identifier is user-defined, which means you can specify identifiers while writing the C language program. While Keywords are predefined, which means the C language has a list of keywords. Let us discuss keywords and identifiers in detail.
In every programming language, there are certain reserved words that are used internally and have some meaning for the language. These words are called Keywords. Keywords help in defining any statement in the program.
Here are some useful points related to Keywords.
We can not use a keyword as an Identifier.
Keywords are always written in lowercase.
Keywords can only contain alphabetical characters.
A keyword is a reserved word whose meaning is already defined in the compiler.
Keywords have fixed meanings, and we can not change the meaning of keywords.
All the words we use in our programs always be keywords or identifiers. Keywords are predefined words and can not be changed by the user, while Identifiers are user-defined words used to give names to entities like variables, functions, arrays, structures, etc. Identifiers are created to provide a unique name to an entity to identify it during the program's execution. For example
int weight;
float height;
In the above example, int and float are Keywords, and weight and height are Identifiers.
The identifier which is used in the external linkage is known as an external identifier. The external identifiers can be function names, global variables.
Internal Identifier
The identifier which is not used in the external linkage is known as an internal identifier. The internal identifiers can be local variables.
Rules for defining Identifiers
The first character of each identifier should be an alphabet or an underscore.
A Keyword cannot be represented as an identifier.
Identifiers should not begin with any numerical digit.
The name should be formed using only letters, numbers, or underscore.
Since C language is case-sensitive, the uppercase and lowercase letters are considered different. For example, value, Value, and VALUE are three different identifiers.
Identifiers are generally given meaningful names. Some valid identifiers names are Value, net_val, _data, mark, etc.
An identifier name may be arbitrarily long. But ANSI standard compilers recognize 31 characters.
How many keywords are in the C language? Ans: There are total 32 keywords in the C language.
What are keywords in C language? Ans: Keywords are words that have special meaning to the C compiler.
What are Identifiers in C language? Ans: Identifiers are words or texts used to identify anything in the C language.
Which format identifier is used for the int data type. Ans: Both %d and %i can be used as a format identifier for the int data type.
Key Takeaways
In this blog, We learned about Keywords, Identifiers, types of Identifiers, and rules for naming Identifiers. We also discussed the difference between a Keyword and an Identifier. This blog is over, but the thirst for learning is not over yet. Use our practice platform Coding Ninjas Studio to practice various DSA questions asked in many interviews. Till then, have a nice day and Happy Coding.
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