What is an identifier in C language?

Identifiers are names used to refer to any entity in a program. (A program can contain many entities (or building blocks) such as data types, constants, variables, functions, arrays, etc. We shall learn about them in the later sections.)An identifier is a sequence of characters. In C, identifiers can be formed by combining alphabets, digits and a special character underscore '_' .For example, consider the program given below:#include <stdio.h>void main() { printf("Hello!");}The tokens main and printf are the names of two functions and are called identifiers.Given below are the rules for creating a valid identifier in C:The first character must always be an alphabet or an underscore. The remaining characters can be a combination of one or more alphabet, digits, and underscores. No special characters except the underscore are allowed in an identifier.An identifier can be of any length. However, in old C (before C was standardized by ANSI), only the first 8 characters were considered by the compilers when the names were compared for equality. This limit was later changed to 31 characters as per the ANSI standard.Click on Live Demo to test and verify the rules for creating valid identifiers in C.Select the correct statements from the given statements.InDia is a valid identifier.Codetantra-software is a valid identifier.An identifier is a sequence of alphabet only._File123 is not a valid identifier._File124_ is not a valid identifier.

Which of the following is an invalid identifier in C?

Read the code given below to learn naming conventions in identifiers.For example, consider the program given below:#include <stdio.h>void main() { int age = 2; // age is an integer variable int firstNumber = 2; // firstNumber is an integer variable // If there are two or more words in an identifier/variable - User can also use "camel case" style to declare a variable. int second_number = 3; // second_number is an integer variable // Any space cannot be used between two words of an identifier/variable; User can use underscore (_) instead of space. int _i_am_also_a_valid_identifier = 4; // _i_am_also_a_valid_identifier is an integer variable // An identifier/variable name must be start with an alphabet or underscore (_) only, no other special characters, digits are allowed as first character of the identifier/variable name. printf("age = %d\n", age); printf("firstNumber = %d\n", firstNumber); printf("second_number = %d\n", second_number); printf("_i_am_also_a_valid_identifier = %d\n", _i_am_also_a_valid_identifier);}Fill in the missing code in the below program to print the values of the given variables.Sample Test CasesTest Case 1:Expected Output:age·=·2firstNumber·=·2second_number·=·3

Choose a valid identifier name according to the naming rules of the C language.

What is the difference between a keyword and an identifier