ISRO CSE 2023 | Question: 22

Question

In the context of parsing techniques, LL$(1)$ refers to:

• A. Grammars that parse the input from left to right, produce a rightmost derivation, with a lookahead of $1$ symbol.
• B. Grammars that parse the input from left to right, produce a leftmost derivation, with a lookahead of $1$ symbol.
• C. Grammars that parse the input from left to right, and backtrack at most once.
• D. Grammars that parse the input from right to left, produce a leftmost derivation, and backtrack at most once.

   

Answer 1

Answer is Option (B)

LL(1) grammer is left to right, left most derivation grammer with 1 lookahead symbol.

(A) False, LL(1) produce left most derivation, not right most.
(B) True.
(C) False, LL(1) does not require backtracking. Reference: scroll down in this link & check diagram.
(D) False, LL(1) parse input left to right, not right to left.

correct me if i am wrong anywhere.