Context Free Grammar


Q1.

Consider the context-free grammar G below S\rightarrow aSb \;| \;X X\rightarrow aX \;| \;Xb \;|\; a\;|\; b where S and X are non-terminals, and a and b are terminal symbols. The starting non-terminal is S. Which one of the following statements is CORRECT?
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Q2.

If G is grammar with productions S\rightarrow SaS|aSb|bSa|SS|\epsilon where S is the start variable, then which one of the following is not generated by G?
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Q3.

Consider the following context-free grammar where the set of terminals is \{a,b,c,d,f\}.\begin{array}{lll} S & \rightarrow & d \: a \: T \mid R \: f \\ T & \rightarrow & a \: S \: \mid \: b \: a \: T \: \mid \epsilon \\ R & \rightarrow & c \: a \: T \: R \: \mid \epsilon \end{array} The following is a partially-filled LL(1) parsing table. Which one of the following choices represents the correct combination for the numbered cells in the parsing table ("blank" denotes that the corresponding cell is empty)?
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Q4.

Consider the following grammar. P\rightarrowxQRS Q\rightarrowyz|zR\rightarroww|\varepsilon S\rightarrowyWhat is FOLLOW (Q) ?
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Q5.

The language which is generated by the grammar S \rightarrow a S a\mid b S b\mid a\mid b over the alphabet of {a,b} is the set of
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Q6.

Which of the following languages is generated by the given grammar? S\rightarrow aS|bS|\varepsilon
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Q7.

Consider the following statements about the context free grammarG=\{S \rightarrow S S, S \rightarrow a b, S \rightarrow b a, S \rightarrow \epsilon\}I. G is ambiguous II. G produces all strings with equal number of a's and b's III. G can be accepted by a deterministic PDA. Which combination below expresses all the true statements about G?
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Q8.

Context free languages are closed under
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Q9.

Consider the following context-free grammar over the alphabet \sum = {a,b,c} with S as the start symbol. S\rightarrowabScT|abcT T\rightarrowbT|b Which one of the following represents the language generated by the above grammar ?
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Q10.

Consider the following expression grammar G: E\rightarrowE-T|T T\rightarrowT+F|F F\rightarrow(E)|id Which of the following grammars is not left recursive, but is equivalent to G?
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