Tokens in C? with example | Types of Tokens in C

 

Tokens in C? with example

Tokens in C programming are fundamental building blocks that make up the source code of a program. They are the smallest units of a C program and include keywords, identifiers, constants, operators, and punctuation marks.

Types of Tokens in C

1. Keywords:

Keywords are reserved words in C that have predefined meanings and cannot be used as identifiers. Examples of C keywords include int, if, while, for, return, and switch.C language supports 32 keywords given below:

auto	double	int	struct
break	else	long	switch
case	enum	register	typedef
char	extern	return	union
const	float	short	unsigned
continue	for	signed	void
default	goto	sizeof	volatile
do	if	static	while

Example:

c
int main() {
    if (x > 0) {
        return 1;
    }
    return 0;
}In the above code, int, if, and return are keywords.

2. Identifiers:

Identifiers are names given to variables, functions, arrays, and other user-defined entities. They must start with a letter or underscore and can be followed by letters, digits, or underscores.

Example:

c
int age;
float salary;
void calculateTotalAmount();

In the code above, age, salary, and calculateTotalAmount are identifiers.

3. Constants:

Constants are values that do not change during program execution. There are various types of constants in C:

Constant	Example
Integer constant	10, 11, 34, etc.
Floating-point constant	45.6, 67.8, 11.2, etc.
Octal constant	011, 088, 022, etc.
Hexadecimal constant	0x1a, 0x4b, 0x6b, etc.
Character constant	'a', 'b', 'c', etc.
String constant	"java", "c++", ".net", etc.

      1.Integer constants:

c
42
0xFF  // Hexadecimal
077   // Octal

           2.Floating-point constants:

c
3.14

2.0e-5

   3.Character constants:

c
'A'
'\n'  // Newline character

    4.String literals:

c
"Hello, World!"

        In the code examples above, 42, 3.14, 'A', and "Hello, World!" are constants.

4. Operators:

C provides various operators for performing operations on data. These include arithmetic, relational, logical, and bitwise operators.Depending on the number of operands, operators are classified as follows:

Unary Operator

A unary operator is an operator applied to the single operand. For example: increment operator (++), decrement operator (--), sizeof, (type)*.

Binary Operator:

The binary operator is an operator applied between two operands. The following is the list of the binary operators:

1. Arithmetic Operators

2. Relational Operators

3. Shift Operators

4. Logical Operators

5. Bitwise Operators

6. Conditional Operators

7. Assignment Operator

8. Misc Operator

Examples:

c
int sum = a + b;    // Addition operator
if (x == y)        // Equality operator
{
    result = 1;
}

In the code above, +, ==, and = are operators.

5. Punctuation:

Punctuation symbols such as parentheses, braces, semicolons, and commas are used to structure C code and separate different elements.

Examples:

c
for (int i = 0; i < 10; i++) {
    printf("Hello, World!\n");
}

In this code, (), {}, ;, and , are punctuation marks.

6. Preprocessor Directives:

Preprocessor directives begin with a # symbol and are used to instruct the C preprocessor to perform actions like including header files and defining macros.

Examples:

c
#include <stdio.h>
#define MAX_VALUE 100

In this code, #include and #define are preprocessor directives.

7. Comments:

Comments are not considered tokens but are essential for adding human-readable explanations within the code. There are two types of comments in C: single-line comments and multi-line comments.

Example:

c
// This is a single-line comment

/*
    This is a
    multi-line comment
*/

Comments are used for documentation and do not affect the program's execution.

In summary, tokens in C programming are the smallest units of a program and include keywords, identifiers, constants, operators, punctuation marks, preprocessor directives, and comments. Understanding these tokens is crucial for writing and comprehending C code effectively.