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GATE | GATE CS 2021 | Set 1 | Question 41

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Consider the following context-free grammar where the set of terminals is {a,b,c,d,f}.

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)?


(A) A
(B) B
(C) C
(D) D


Answer: (A)

Explanation:

Let’s Compute First and Follow of non terminals.

  First  Follow
S d,c,f c,f,$
T a,b,∈ c,f,$
R c,∈ f

Now using first and follow we will construct LL(1) parsing table.

1. S ->Rf production entry  will come under first of S terminals (c,f) in parsing table. 

2. T->∈ production entry  will come under follow of T terminals (c,f,$) in parsing table.

  a b c d f $
S     S ->Rf S->daT S ->Rf  
T T->aS T->baT T->∈   T->∈ T->∈
R     R->caTR   R->∈  



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Last Updated : 01 Sep, 2021
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