What are tokens in C LANGUAGE? - Tokens kya hote hai - C language mein token kese kam karte hai - Token in C

 What are tokens in C LANGUAGE?

In the context of the C programming language, a "token" refers to the smallest unit of source code, which the compiler recognizes and processes. Tokens are the building blocks of a C program, and they are used to form statements, expressions, and other language constructs.

 

There are several types of tokens in C:

 

1. Keywords: These are reserved words that have special meanings in C and cannot be used as identifiers (e.g., `if`, `else`, `for`, `while`).

 

2. Identifiers: Identifiers are names given to various program elements such as variables, functions, arrays, etc. They consist of letters, digits, and underscores, and they must start with a letter or an underscore.

 

3. Constants: Constants represent fixed values that cannot be modified during program execution. Examples include integer constants, floating-point constants, character constants, and string constants.

 

4. String literals: These are sequences of characters enclosed in double-quotes.

 

5. Operators: Operators perform operations on operands. Examples include arithmetic operators (+, -, *, /), relational operators (==, !=, <, >), logical operators (&&, ||, !), etc.

 

6. Punctuation: These include punctuation symbols such as semicolons (;), commas (,), parentheses (()), braces ({ }), and brackets ([]).

 

7. Comments: Comments are used to annotate the code and are ignored by the compiler. There are two types of comments in C: single-line comments (`//`) and multi-line comments (`/* */`).

 

8. Preprocessor directives: These are commands to the preprocessor, which manipulate the source code before actual compilation. Preprocessor directives start with `#` (e.g., `#include`, `#define`).

 

9. Whitespace: Whitespace characters (spaces, tabs, newlines) are used for formatting and separating tokens but are generally ignored by the compiler.

 

Tokens are important in the compilation process because the compiler processes the source code by analyzing and categorizing these tokens according to the rules of the C language.

What is constant in C LANGUAGE?

In the C programming language, a constant is a value that cannot be altered or modified during the execution of a program. Constants represent fixed values that remain unchanged throughout the program's execution. Constants are used to store data that should not be modified by the program. 

There are several types of constants in C: 

1. Integer Constants: These are whole numbers without a decimal point. They can be expressed in different bases: decimal (base 10), octal (base 8), or hexadecimal (base 16). For example:

   int decimalConstant = 42;     // Decimal constant

   int octalConstant = 052;      // Octal constant (starts with 0)

   int hexConstant = 0x2A;       // Hexadecimal constant (starts with 0x)

2. Floating-Point Constants: These are numbers with a decimal point or in exponential notation. For example: 

   float floatConstant = 3.14;   // Floating-point constant

3. Character Constants: These represent individual characters and are enclosed in single quotes. For example:

   char charConstant = 'A';      // Character constant

4. String Constants: These are sequences of characters enclosed in double quotes. For example:

   char stringConstant[] = "Hello, World!"; // String constant

5. Enumeration Constants: These are identifiers defined using the `enum` keyword to represent a set of related named constants. For example:

   enum Colors { RED, GREEN, BLUE }; // Enumeration constants

Constants provide a way to make programs more readable, maintainable, and efficient by allowing programmers to assign meaningful names to values that will remain constant throughout the program.