GATE CSE Context-Free Languages, Grammars & Pushdown Automata – TOC Practice Test

GATE CSE Context-Free Languages, Grammars & Pushdown Automata – TOC Practice Test | Set 1

Questions 46-50 of 100

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Question 46

MCQ · Single Correct 1 mark

Which language is a classic inherently ambiguous CFL?

A ${a^n b^n | n>=0}$ B {$a^i$ $b^j$ $c^k$ | $i=j$ or $j=k}$ C {ww^R | w in {a,b}*} D ${a^n b^m | n,m>=0}$

Question 47

MCQ · Single Correct 1 mark

Which statement about inherently ambiguous CFLs is correct?

A They are always regular B They have at least one unambiguous grammar C They are not context-free D Every grammar for the language is ambiguous

Question 48

MCQ · Single Correct 1 mark

In the CFL pumping lemma, a pumped string is commonly written as which form?

A xyz B uvwxy C abcde with all parts nonempty D pqrs

Question 49

MCQ · Single Correct 1 mark

Which language is a CFL?

A ${a^n b^n c^n d^n | n>=0}$ B ${a^n b^n c^n | n>=0}$ C {ww | w in {a,b}*} D ${a^n b^m | n,m>=0}$

Question 50

MCQ · Single Correct 1 mark

Which statement about CFG ambiguity is correct?

A Every CFL has a unique parse tree for every string B A CFG is ambiguous if some string has two distinct parse trees C Ambiguity is always removed by eliminating $\epsilon-productions$ D An ambiguous grammar cannot generate a CFL