Syntax Analysis MCQs
What is the primary goal of syntax analysis in a compiler?
A) To convert source code into machine code
B) To check the syntax of the source code and generate parse trees
C) To optimize the performance of the program
D) To manage memory allocation
Answer: B
Which of the following is a common data structure used in syntax analysis?
A) Array
B) Stack
C) Queue
D) Binary Tree
Answer: B
What does a parse tree represent in syntax analysis?
A) The sequence of tokens in the source code
B) The grammatical structure of the source code
C) The memory layout of the program
D) The output of the compiler
Answer: B
Which parsing technique uses a stack to keep track of the parsing process?
A) Top-down parsing
B) Bottom-up parsing
C) Recursive descent parsing
D) Shift-reduce parsing
Answer: B
In which type of parsing is the input processed from left to right and the parse tree is built from the leaves to the root?
A) Top-down parsing
B) Bottom-up parsing
C) Predictive parsing
D) LL parsing
Answer: B
What is an LR parser used for?
A) To handle top-down parsing
B) To handle bottom-up parsing
C) To generate intermediate code
D) To optimize the code
Answer: B
Which of the following is a characteristic of LL parsers?
A) They use a stack-based approach.
B) They build the parse tree from the leaves to the root.
C) They are used for bottom-up parsing.
D) They require the grammar to be left-recursive.
Answer: A
Which grammar type is suitable for LL parsing?
A) Context-free grammar
B) Context-sensitive grammar
C) Regular grammar
D) Unrestricted grammar
Answer: A
What is a syntax tree used for in syntax analysis?
A) To represent the structure of the source code based on grammar rules
B) To execute the source code
C) To optimize the source code
D) To manage memory allocation
Answer: A
In an LL(1) parser, what does the ‘1’ denote?
A) The number of lookahead tokens
B) The number of grammar rules
C) The number of recursive functions
D) The number of states in the parser
Answer: A
What does a shift operation do in a shift-reduce parser?
A) It moves the next input token onto the stack.
B) It reduces the top stack elements to a non-terminal.
C) It shifts the parse tree.
D) It updates the grammar rules.
Answer: A
Which parsing technique is most suited for dealing with left-recursive grammars?
A) Recursive descent parsing
B) LL parsing
C) LR parsing
D) SLR parsing
Answer: C
What is the main advantage of using a recursive descent parser?
A) It can handle any context-free grammar.
B) It is easy to implement and understand.
C) It does not require lookahead tokens.
D) It automatically generates parse tables.
Answer: B
Which of the following is not a type of LR parser?
A) SLR (Simple LR)
B) LALR (Look-Ahead LR)
C) Canonical LR
D) CLR (Canonical LR)
Answer: D
What is the primary use of a parsing table in a parser?
A) To store the rules for error handling
B) To map input tokens to grammar rules
C) To keep track of memory allocation
D) To optimize the parsing process
Answer: B
Which type of grammar is used with a recursive descent parser?
A) Left-recursive grammar
B) Right-recursive grammar
C) Non-recursive grammar
D) Unrestricted grammar
Answer: B
In syntax analysis, what is a lookahead token used for?
A) To determine the next parsing action
B) To store intermediate parse trees
C) To manage stack operations
D) To handle syntax errors
Answer: A
What is the function of the goto table in an LR parser?
A) It directs the parser to the next state based on the current state and input token.
B) It stores the grammar rules for reduction.
C) It manages lookahead tokens.
D) It initializes the parse table.
Answer: A
What type of parser uses a top-down approach to build the parse tree?
A) LL parser
B) LR parser
C) SLR parser
D) LALR parser
Answer: A
What is the purpose of the reduce operation in shift-reduce parsing?
A) To replace the top stack elements with a non-terminal
B) To move the next input token onto the stack
C) To update the parse table
D) To handle syntax errors
Answer: A
What is the main limitation of LL parsers?
A) They cannot handle left-recursive grammars.
B) They are inefficient for large input files.
C) They require a lot of memory.
D) They cannot generate parse trees.
Answer: A
Which of the following is a characteristic of an SLR parser?
A) It uses a single lookahead token.
B) It can handle left-recursive grammars.
C) It does not use a parsing table.
D) It generates fewer states than a canonical LR parser.
Answer: D
What is the purpose of a parser generator tool like Yacc?
A) To automatically generate parsers based on grammar specifications
B) To optimize the performance of the lexer
C) To manage memory allocation
D) To execute source code
Answer: A
In syntax analysis, what is an ambiguous grammar?
A) A grammar that can produce more than one parse tree for a given input
B) A grammar with undefined rules
C) A grammar that cannot be parsed by any parser
D) A grammar that requires multiple lookahead tokens
Answer: A
Which parsing technique is known for handling ambiguous grammars?
A) Recursive descent parsing
B) LR parsing
C) LL parsing
D) Top-down parsing
Answer: B
What is the primary function of a shift operation in a shift-reduce parser?
A) To move the next token onto the stack for further processing
B) To reduce the stack elements to a non-terminal
C) To handle syntax errors
D) To initialize the parser
Answer: A
In which parsing technique is the input processed from left to right, and the parse tree is built from the top down?
A) LL parsing
B) LR parsing
C) SLR parsing
D) LALR parsing
Answer: A
Which table in an LR parser is used to determine the actions to be taken based on the current state and input token?
A) Action table
B) Goto table
C) Parsing table
D) Syntax table
Answer: A
What does an LALR parser combine to improve efficiency over a canonical LR parser?
A) Multiple states with similar parsing actions
B) Additional lookahead tokens
C) Recursive functions
D) Larger parsing tables
Answer: A
What is the purpose of a semantic action in syntax analysis?
A) To perform actions such as building the parse tree or symbol table during parsing
B) To manage the memory allocation
C) To handle syntax errors
D) To optimize the performance of the lexer
Answer: A
What is the key feature of a top-down parser?
A) It tries to construct the parse tree from the start symbol to the leaves.
B) It processes the input from the leaves to the root.
C) It uses a stack to manage the parsing process.
D) It generates parse tables dynamically.
Answer: A
Which of the following can be a result of an ambiguous grammar?
A) Multiple valid parse trees for a single input
B) A parse tree with only one valid interpretation
C) An error in the grammar rules
D) A parser that cannot be constructed
Answer: A
In syntax analysis, what does the yyparse() function do?
A) It initiates the parsing process using the grammar rules defined.
B) It generates the lexing rules.
C) It manages memory allocation for the parse tree.
D) It handles syntax errors.
Answer: A
Which of the following is true about a predictive parser?
A) It uses lookahead tokens to decide which production to use.
B) It processes the input from right to left.
C) It does not require a parsing table.
D) It can handle any context-free grammar.
Answer: A
What is the function of the yyerror() function in syntax analysis?
A) To handle and report syntax errors during parsing
B) To initialize the lexer
C) To manage input tokens
D) To optimize the parse tree
Answer: A
Which technique is used for handling left recursion in parsing?
A) Rewrite the grammar to remove left recursion
B) Use a top-down parser
C) Implement multiple lookahead tokens
D) Use a stack-based approach
Answer: A
In a shift-reduce parser, what triggers a reduce operation?
A) When a sequence of stack symbols matches the right-hand side of a grammar rule
B) When a new token is shifted onto the stack
C) When the parser encounters an error
D) When the input stream is exhausted
Answer: A
What does the yywrap() function do in a lexical analyzer?
A) It handles end-of-file conditions by providing new input files.
B) It manages the parsing table.
C) It generates semantic actions.
D) It initializes the lexer.
Answer: A
Which parser uses a stack to handle grammar rules and tokens?
A) Recursive descent parser
B) LL parser
C) LR parser
D) LALR parser
Answer: C
Which parsing method requires that the grammar be free of left recursion?
A) LL parsing
B) LR parsing
C) SLR parsing
D) LALR parsing
Answer: A
In syntax analysis, what is a non-terminal symbol?
A) A symbol that can be replaced by one or more terminal symbols according to grammar rules
B) A symbol that appears only in the final parse tree
C) A symbol that denotes an end-of-file condition
D) A symbol that represents a specific token
Answer: A
What is the function of a lookahead token in an LL(1) parser?
A) To decide which production rule to apply next based on the current input token
B) To manage memory allocation for the parse tree
C) To handle syntax errors
D) To initialize the parser
Answer: A
Which type of grammar is generally used with a shift-reduce parser?
A) Context-free grammar
B) Regular grammar
C) Context-sensitive grammar
D) Unrestricted grammar
Answer: A
Which parser is known for its ability to handle a wide range of context-free grammars, including ambiguous ones?
A) LR parser
B) LL parser
C) Recursive descent parser
D) SLR parser
Answer: A
What is the main disadvantage of using recursive descent parsing?
A) It cannot handle left-recursive grammars.
B) It is difficult to implement.
C) It requires complex parsing tables.
D) It cannot generate parse trees.
Answer: A
In which parsing method is a grammar rule applied based on the next input token?
A) Predictive parsing
B) Shift-reduce parsing
C) Recursive descent parsing
D) LR parsing
Answer: A
Which data structure is used to keep track of active parsing states in an LR parser?
A) Stack
B) Queue
C) List
D) Tree
Answer: A
In syntax analysis, what is a terminal symbol?
A) A symbol that appears in the final output of the parse tree
B) A symbol that denotes a non-terminal in the grammar
C) A symbol used only for internal parsing purposes
D) A symbol that represents a specific token type
Answer: D
Which function is typically responsible for error handling in a syntax analyzer?
A) yyerror()
B) yyparse()
C) yylex()
D) yywrap()
Answer: A
What is the main feature of an SLR parser compared to a canonical LR parser?
A) It uses fewer states and is simpler to implement.
B) It handles more complex grammars.
C) It requires more memory.
D) It generates more complex parse tables.
Answer: A