Tokens in C language are the smallest individual units of a program, such as keywords, identifiers, constants, operators, and special symbols. Here’s an explanation of each type of token with examples:
- Keywords:
- Keywords are reserved words that have predefined meanings in C language.
- Example:
int
,if
,else
,for
,while
,return
,void
,struct
, etc.
- Identifiers:
- Identifiers are names given to various program elements such as variables, functions, arrays, etc.
- Rules for identifiers: They must begin with a letter (uppercase or lowercase) or an underscore (_), followed by letters, digits, or underscores.
- Example:
sum
,i
,MAX_SIZE
,calculateArea
,first_name
, etc.
- Constants:
- Constants are fixed values that do not change during program execution.
- Types of constants include integer constants, character constants, floating-point constants, and string constants.
- Example integer constant:
10
,-20
,0xFF
(hexadecimal),077
(octal), etc. - Example character constant:
'A'
,'b'
,'7'
,'%'
, etc. - Example floating-point constant:
3.14
,-0.0012
,2.0E-5
, etc. - Example string constant:
"Hello"
,"123"
,"C programming"
, etc.
- Operators:
- Operators perform operations on operands.
- Types of operators include arithmetic operators, relational operators, logical operators, assignment operators, etc.
- Example arithmetic operators:
+
,-
,*
,/
,%
. - Example relational operators:
==
,!=
,<
,>
,<=
,>=
. - Example logical operators:
&&
(AND),||
(OR),!
(NOT). - Example assignment operators:
=
,+=
,-=
etc.
- Special Symbols:
- Special symbols include punctuation marks and other symbols used in C syntax.
- Example:
;
(semicolon),,
(comma),{}
(curly braces),()
(parentheses),[]
(square brackets),.
(dot),->
(arrow), etc.
- Whitespace:
- Whitespace includes spaces, tabs, and newlines.
- Whitespace is used to separate tokens but is otherwise ignored by the compiler.
- Example: Spaces between keywords, identifiers, operators, etc.
Example:
#include <stdio.h> Â int main() { Â Â Â Â int num1 = 10; Â Â Â Â int num2 = 20; Â Â Â Â int sum; Â Â Â Â Â sum = num1 + num2; Â Â Â Â Â Â Â Â Â printf("The sum is: %d\n", sum); Â Â Â Â Â Â Â Â Â return 0; }
In this example:
- Keywords:
int
,return
,void
. - Identifiers:
main
,num1
,num2
,sum
. - Constants:
10
,20
,0
. - Operators:
=
,+
. - Special Symbols:
{
,}
,=
,;
,()
,,
,"\n"
. - Whitespace: Spaces, newlines.
Team Edited answer April 13, 2024