GATE CS 2024 Set 1 — Question 26

MSQ+1 / -0EasySyntax AnalysisCompiler Design

Compiler Design → Syntax Analysis

Last updated 20 August 2026

Question

Which of the following is/are Bottom-Up Parser(s)?

Correct answer (A) Shift-reduce Parser; (D) LR Parser Solution Bottom-up parsing constructs the parse tree from the leaves (input string) up to the root (start symbol). 1. Shift-reduce Parser: This is a general style of bottom-up parsing where the parser shifts input symbols onto a stack and reduces a string of symbols on the top of the stack to a non-terminal according to the grammar rules. Thus, it is a bottom-up parser. 2. Predictive Parser: This is typically a recursive descent parser (top-down) that does not require backtracking. It predicts which production to use based on the lookahead. Thus, it is a top-down parser. 3. LL(1) Parser: LL parsers (Left-to-right scan, Leftmost derivation) are top-down parsers. 4. LR Parser: LR parsers (Left-to-right scan, Rightmost derivation in reverse) are a type of shift-reduce parser and are therefore bottom-up parsers. Therefore, options (A) and (D) are correct. Turn this into a strength. Explore AI-powered practice and doubt support with Success Tracker.

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Correct answer (A) Shift-reduce Parser; (D) LR Parser Solution Bottom-up parsing constructs the parse tree from the leaves (input string) up to the root (start symbol). 1. Shift-reduce Parser: This is a general style of bottom-up parsing where the parser shifts input symbols onto a stack and reduces a string of symbols on the top of the stack to a non-terminal according to the grammar rules. Thus, it is a bottom-up parser. 2. Predictive Parser: This is typically a recursive descent parser (top-down) that does not require backtracking. It predicts which production to use based on the lookahead. Thus, it is a top-down parser. 3. LL(1) Parser: LL parsers (Left-to-right scan, Leftmost derivation) are top-down parsers. 4. LR Parser: LR parsers (Left-to-right scan, Rightmost derivation in reverse) are a type of shift-reduce parser and are therefore bottom-up parsers. Therefore, options (A) and (D) are correct.

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