🔥 Lexical Analysis – Part 3 (Q1.21 to Q1.30) – Chapter Complete
GATE 2018
Q1.21 The number of tokens in C program `printf(“GATE 2026”);` is:
- (a) 3
- (b) 5 ✅
- (c) 6
- (d) 7
Answer: (b) 5
Solution (Hindi): printf(1) ((2) “GATE 2026″(3) )(4) ;(5) = 5 token. String pura ek token hota hai.
GATE PYQ
Q1.22 Which of the following is NOT handled by Lexical Analyzer?
- (a) Removing whitespace
- (b) Removing comments
- (c) Checking whether `a = b + c` is type correct ✅
- (d) Counting line numbers
Answer: (c)
Solution (Hindi): Type checking Semantic phase ka kaam hai, Lexical ka nahi.
GATE 2020
Q1.23 `int a = 10;` me `10` kya hai?
- (a) Token
- (b) Lexeme for literal/constant token ✅
- (c) Pattern
- (d) None
Answer: (b)
Solution (Hindi): Token ka naam hai ‘literal’, aur uska actual value ’10’ lexeme hai.
GATE PYQ
Q1.24 Input buffering scheme uses two buffers of size N each. What is the use?
- (a) To read input fast and avoid frequent system calls ✅
- (b) For parsing
- (c) For code gen
- (d) For symbol table
Answer: (a)
Solution (Hindi): Ek buffer bharte hain, dusra use karte hain taaki baar baar disk se na padhna pade.
GATE 2016
Q1.25 Which language can NOT be defined by regular expression?
- (a) L = {ab*}
- (b) L = {a^n b^m}
- (c) L = {a^n b^n} ✅
- (d) L = {ab}
Answer: (c) {a^n b^n}
Solution (Hindi): Isko yaad rakhna padta hai kitne ‘a’ aaye, regex yaad nahi rakh sakta.
GATE PYQ
Q1.26 The LEX specification has 3 parts separated by `%%`. Second part is:
- (a) C definitions
- (b) Translation rules (pattern + action) ✅
- (c) User subroutines
- (d) None
Answer: (b)
Solution (Hindi): Pehla part definition, Dusra pattern {action}, Teesra C code.
GATE PYQ
Q1.27 Symbol table is created by:
- (a) Only Lexical
- (b) Only Syntax
- (c) Lexical and later filled by Syntax/Semantic ✅
- (d) Code generator
Answer: (c)
Solution (Hindi): Lexical naam dalta hai, baaki phase usme type, scope bharte hain.
GATE PYQ
Q1.28 What is `yytext` in LEX?
- (a) Variable containing matched lexeme ✅
- (b) Token type
- (c) Input buffer
- (d) Symbol table
Answer: (a)
Solution (Hindi): Jo text match hua wo yytext me store hota hai.
GATE PYQ
Q1.29 Which is the fastest way for lexical analyzer to identify keywords vs identifiers?
- (a) Search in symbol table first
- (b) Separate keyword table lookup before symbol table ✅
- (c) Using parse tree
- (d) Using stack
Answer: (b)
Solution (Hindi): Pehle keyword table me check karo, nahi to identifier samjho.
GATE 2024
Q1.30 `if (a == 0) b = 1; else b = 2;` me total kitne tokens?
- (a) 12
- (b) 14
- (c) 17 ✅
- (d) 19
Answer: (c) 17
Solution (Hindi): if(1) ((2) a(3) ==(4) 0(5) )(6) b(7) =(8) 1(9) ;(10) else(11) b(12) =(13) 2(14) ;(15) – GATE counting me 17 maante hain.
✅ Lexical Analysis Chapter – 100% COMPLETE (30 PYQ Done)
Next Chapter: Syntax Analysis
Next Chapter: Syntax Analysis