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Lexical Analysis - compiler design IT & Software Notes | EduRev

IT & Software : Lexical Analysis - compiler design IT & Software Notes | EduRev

 Page 1


Lexical Analysis 
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Lexical Analysis 
The Scanner 
? The job of the scanner is to read characters 
from the source code and form them into 
tokens.  
? Token classes include: 
– Identifiers 
– Literals (numeric, string, character) 
– Keywords and reserved words 
– Operators 
– Others 
Page 3


Lexical Analysis 
The Scanner 
? The job of the scanner is to read characters 
from the source code and form them into 
tokens.  
? Token classes include: 
– Identifiers 
– Literals (numeric, string, character) 
– Keywords and reserved words 
– Operators 
– Others 
Representing Tokens 
? using the #define macro (C/C++): 
 
 #define IF 256 
 #define THEN 257 
 #define ELSE 258 
 ... 
Page 4


Lexical Analysis 
The Scanner 
? The job of the scanner is to read characters 
from the source code and form them into 
tokens.  
? Token classes include: 
– Identifiers 
– Literals (numeric, string, character) 
– Keywords and reserved words 
– Operators 
– Others 
Representing Tokens 
? using the #define macro (C/C++): 
 
 #define IF 256 
 #define THEN 257 
 #define ELSE 258 
 ... 
Representing Tokens 
? Using named constants (Java): 
 
 public static final IF = 256; 
 public static final THEN = 257; 
 public static final ELSE = 258; 
 ... 
Page 5


Lexical Analysis 
The Scanner 
? The job of the scanner is to read characters 
from the source code and form them into 
tokens.  
? Token classes include: 
– Identifiers 
– Literals (numeric, string, character) 
– Keywords and reserved words 
– Operators 
– Others 
Representing Tokens 
? using the #define macro (C/C++): 
 
 #define IF 256 
 #define THEN 257 
 #define ELSE 258 
 ... 
Representing Tokens 
? Using named constants (Java): 
 
 public static final IF = 256; 
 public static final THEN = 257; 
 public static final ELSE = 258; 
 ... 
Representing Tokens 
? Token classes may have attributes 
– Identifiers have a string name 
– Numeric literals have a value 
– Relational operators have 1 of 6 values 
? We need more than a single scalar object to 
represent tokens. 
– struct 
– class

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Rashmi Sehgal

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370

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Lexical Analysis - compiler design IT & Software Notes | EduRev notes for IT & Software is made by best teachers who have written some of the best books of IT & Software. It has gotten 370 views and also has 0 rating. You can download Free Lexical Analysis - compiler design IT & Software Notes | EduRev pdf from EduRev by using search above. You can also find Lexical Analysis - compiler design IT & Software Notes | EduRev ppt and other IT & Software slides as well. If you want Lexical Analysis - compiler design IT & Software Notes | EduRev Tests & Videos, you can search for the same too. IT & Software Lexical Analysis - compiler design IT & Software Notes | EduRev Summary and Exercise are very important for perfect preparation. You can see some Lexical Analysis - compiler design IT & Software Notes | EduRev sample questions with examples at the bottom of this page. Complete Lexical Analysis - compiler design IT & Software Notes | EduRev chapter (including extra questions, long questions, short questions, mcq) can be found on EduRev, you can check out IT & Software lecture & lessons summary in the same course for IT & Software Syllabus. EduRev is like a wikipedia just for education and the Lexical Analysis - compiler design IT & Software Notes | EduRev images and diagram are even better than Byjus! Do check out the sample questions of Lexical Analysis - compiler design IT & Software Notes | EduRev for IT & Software, the answers and examples explain the meaning of chapter in the best manner. This is your solution of Lexical Analysis - compiler design IT & Software Notes | EduRev search giving you solved answers for the same. To Study Lexical Analysis - compiler design IT & Software Notes | EduRev for IT & Software this is your one stop solution.

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