Compiler Design NTA UGC NET Question Analysis
| Q.1➡ | UGC NET DEC 2023 Three address codes can be represented in special structures known as: (A) Quadruples (B) Triples (C) Patterns (D) Indirect Triples Choose the correct answer from the options given below : |
| i ➥ (A) and (B) Only |
| ii ➥ (A), (B) and (D) Only |
| iii ➥ (B) and (C) Only |
| iv ➥ (B), (C) and (D) Only |
| Best Explanation: Answer: (III) Explanation: Upload Soon |
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| Q.2➡ | UGC NET DEC 2023 Consider a Grammar E→E+n | E x n | n for a sentence n+n×n, the handles in the right-sentential form of the reduction are? |
| i ➥ n, E+n and E+n×n |
| ii ➥ n, E+n and E+Exn |
| iii ➥ n, n+n and n+n×n |
| iv ➥ n, E+n and Exn |
| Best Explanation: Answer: (IV) Explanation: Upload Soon |
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| Q.3➡ | UGC NET DEC 2023 One of the purposes of using intermediate code in compilers is to: |
| i ➥ make parsing and semantic analysis simpler |
| ii ➥ improve error recovery and error reporting |
| iii ➥ increase the chances of reusing the machine independent code optimizer in other compilers |
| iv ➥ improve the register allocation |
| Best Explanation: Answer: (III) Explanation: Upload Soon |
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| Q.4➡ | UGC NET DEC 2023 Arrange the following phases of a compiler as per their order of execution (start to end) (A) Target code generation (B) Syntax Analysis (C) Code optimization (D) Semantic Analysis (E) Lexical Analysis Choose the correct answer from the options given below : |
| i ➥ (B), (E), (D), (A), (C) |
| ii ➥ (E), (D), (B), (A), (C) |
| iii ➥ (E), (B), (D), (C), (A) |
| iv ➥ (B), (D), (Ε), (A), (C) |
| Best Explanation: Answer: (III) Explanation: Upload Soon |
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| Q.5➡ | UGC NET DEC 2023 Match List – I with List – II according to input to the compiler phase that process it : List – I (A) Syntax tree (B) Intermediate representation (C) Token stream (D) Character stream List – II (I) Code generator (II) Semantic analyzer (III) Lexical analyze (IV) Syntax analyser Choose the correct answer from the options given below : |
| i ➥ (A)-(IV), (B)-(III), (C)-(I), (D)-(II) |
| ii ➥ (A)-(II), (B)-(I), (C)-(IV), (D)-(III) |
| iii ➥ (A)-(II), (B)-(IV), (C)-(I), (D)-(III) |
| iv ➥ (A)-(IV), (B)-(I), (C)-(II), (D)-(III) |
| Best Explanation: Answer: (II) Explanation: Upload Soon |
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| Q.6➡ | UGC NET JUNE 2023 The compiler for high level language that runs on one machine and produces code for other machine is called- |
| i ➥ Cross compiler |
| ii ➥ Multipass compiler |
| iii ➥ Optimizing Compiler |
| iv ➥ One pass Compiler |
| Best Explanation: Answer: I (*) Explanation: It is a defination of Cross compiler A Two pass/multi-pass Compiler is a type of compiler that processes the source code or abstract syntax tree of a program multiple times. In multipass Compiler, we divide phases into two passes as: First Pass: is refers as (a). Front end (b). Analytic part (c). Platform independent Second Pass: is refers as (a). Back end (b). Synthesis Part (c). Platform Dependent |
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| Q.7➡ | UGC NET JUNE 2023 The maximum yield length of the following CNF CFG is S→AB A→CD B→e C→a D→b |
| i ➥ 8 |
| ii ➥ 7 |
| iii ➥ 4 |
| iv ➥ 5 |
| Best Explanation: Answer: iii Explanation: Upload Soon |
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| Q.8➡ | UGC NET JUNE 2023 Which of the following parser is most powerful parser? |
| i ➥ Operator precedence |
| ii ➥ SLR |
| iii ➥ Canonical LR |
| iv ➥ LALR |
| Best Explanation: Answer: C Explanation: Upload Soon |
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| Q.9➡ | UGC NET JUNE 2023 Which phase of compiler checks the grammar of programming? |
| i ➥ Code optimization |
| ii ➥ Semantic analysis |
| iii ➥ Code generators |
| iv ➥ Syntax analysis |
| Best Explanation: Answer: IV Explanation: Upload Soon |
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| Q.10➡ | NET December 20222 The item generated by the production A → ɛ is : |
| i ➥ A →. |
| ii ➥ A → ɛ. |
| iii ➥ A → .ɛ |
| iv ➥ A → ɛ |
| Best Explanation: Answer: (i) Explanation: Upload Soon |
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| Q.11➡ | NET December 2022 Which of the following statements are correct? (A) The first three address instruction in the intermediate code is a leader. (B) The instruction which is exactly at the middle of the given three address code is a leader. (C) Any instruction that is the target of a conditional or unconditional jump is a leader. (D) Any instruction that immediately follows a conditional or unconditional jump is a leader. Choose the correct answer from the options given below: |
| i ➥ A, B and C |
| ii ➥ B, C and D |
| iii ➥ A, C and D |
| iv ➥ A, B, C and D |
| Best Explanation: Answer: (iii) Explanation: Upload Soon |
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| Q.12➡ | NET June 2022 Consider the grammar S—>SbS|a. Consider the following statements: (A) Two Parse tree (B) Two left most derivation (C) Two right most derivation Which of the following is correct? |
| i ➥ All (A), (B) and (C) are true |
| ii ➥ Only (B) is true |
| iii ➥ Only (C) is true |
| iv ➥ Only (A) is true |
| Best Explanation: Answer: (iv) Explanation: Upload Soon |
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| Q.13➡ | NET June 2022 Consider the following statements: Statement (I) : LALR Parser is more powerful than canonical LR parser Statement (II) : SLR parser is more powerful that LALR Which of the following is correct? |
| i ➥ Statement (I) true and statement (II) false |
| ii ➥ Statement (I) false and statement (II) true |
| iii ➥ Both statement (I) and Statement (II) false |
| iv ➥ Both statement (I) and statement (II) true |
| Best Explanation: Answer: (iii) Explanation: Upload Soon |
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| Q.14➡ | NET June 2021 Given below are two statements Statement I: LL(1) and LR are examples of Bottom-up parsers. Statement II: Recursive descent parser and SLR are examples of Top-down parsers In light of the above statements, choose the correct answer from the options given below Options:- |
| i ➥ Both Statement I and Statement II are false |
| ii ➥ Both Statement I and Statement II are true |
| iii ➥ Statement I is false but Statement II is true |
| iv ➥ Statement I is true but Statement II is false |
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| Q.15➡ | NTA UGC NET November 2020 Which of the following grammars is (are) ambiguous? (A) s → ss | asb | bsa | λ (B) s → asbs | bsas | λ (C) s → aAB A → bBb B → A | λ where λ denotes empty string Choose the correct answer from the options given below: |
| i➥ (A) and (C) only |
| ii ➥ (B) only |
| iii ➥ (B) and (C) only |
| iv ➥ (A) and (B) only |
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| Q.16➡ | NTA UGC NET November 2020 Which of the following are applications of symbol table? A) Storage allocation B) Checking type compatibility C) Suppressing duplicate error messages Choose the correct answer from the options given below: |
| i➥ (A) and (B) only |
| ii ➥ (A) and (C) only |
| iii ➥ (B) and (C) only |
| iv ➥ (A), (B) and (C) only |
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| Q.17➡ | NTA UGC NET November 2020 Which of the following is not an intermediate code form? |
| i➥ Syntax trees |
| ii ➥ Three address codes |
| iii ➥ Quadruples |
| iv ➥ Post fix Notation |
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| Q.18➡ | NTA UGC NET December 2019 Which of the component module of DBMS does rearrangement and possible ordering of operations, eliminate redundancy in query and use efficient algorithms and indexes during the execution of a query? |
| i➥ Query compiler |
| ii ➥ Query optimizer |
| iii ➥ Stored data manager |
| iv ➥ Database processor |
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| Q.19➡ | NTA UGC NET June 2019 Replacing the expression 4*2.14 by 8.56 is known as |
| i➥ Constant folding |
| ii ➥ Induction variable |
| iii ➥ Strength reduction |
| iv ➥ Code reduction |
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| Q.20➡ | NTA UGC NET June 2019 Which data structure is used by the compiler for managing variables and their attributes? |
| i➥ Binary tree |
| ii ➥ link list |
| iii ➥ Symbol table |
| iv ➥ Parse table |
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| Q.21➡ | NTA UGC NET June 2019 Shift-reduce parser consists of (a) input buffer (b) stack (c) parse table choose the correct option from those given below: |
| i➥ (a) and (b) only |
| ii ➥ (a) and (c) only |
| iii ➥ (c) only |
| iv ➥ (a), (b) and (c) |
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| Explanation: Components of a shift-reduce parser: Stack: The stack is a data structure that holds a sequence of grammar symbols or states during the parsing process. Initially, it contains only the bottom-of-stack marker (often denoted by $) to indicate an empty stack. Input Buffer: The input buffer is a buffer that holds the remaining input to be parsed. It initially contains the entire input string. Parsing Table: The parsing table is a key data structure that guides the parser’s actions. It typically contains information about state transitions and actions to be taken based on the current state of the parser and the next input symbol. Shift Operation: The shift operation involves moving a symbol from the input buffer to the top of the stack. This operation reflects the parser’s recognition of a portion of the input that matches a valid part of the grammar. Reduce Operation: The reduce operation involves replacing a group of symbols on the top of the stack with a non-terminal symbol, according to a production in the grammar. This operation is applied when a portion of the input matches the right-hand side of a production. Accept Operation: The accept operation is performed when the entire input has been successfully parsed, and the stack contains only the start symbol. This indicates that the input conforms to the grammar. Error Handling: Shift-reduce parsers need mechanisms for error detection and recovery. If the input cannot be successfully parsed, error-handling routines are invoked to handle the issue gracefully. The shift-reduce parsing process involves a series of shifts and reduces until the entire input is reduced to the start symbol, or an error is detected. The parsing table dictates the actions to be taken at each step, depending on the current state and the next input symbol. |
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| Q.22➡ | NTA UGC NET June 2019 On translating the expression given below into quadruple representation, how many operations are required? (i*j)+(e+f)*(a*b+c) |
| i➥ 5 |
| ii ➥ 6 |
| iii ➥ 3 |
| iv ➥ 7 |
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| Q.23➡ | NTA UGC NET December 2018 The grammar S ⟶ (S) | SS | ∈ is not suitable for predictive parsing because the grammar is |
| i➥ An Operator Grammar |
| ii ➥ Right Recursive |
| iii ➥ Left Recursive |
| iv ➥ Ambiguous |
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| Q.24➡ | NTA UGC NET December 2018 Consider the following Grammar G : S ➝ A | B A➝ a | c B➝ b | c Where {S,A,B} is the set of non-terminals, {a,b,c} is the set of terminals. Which of the following statement(s) is/are correct ? S1 : LR(1) can parse all strings that are generated using grammar G. S2 : LL(1) can parse all strings that are generated using grammar G. |
| i➥ Both S1 and S2 |
| ii ➥ Only S2 |
| iii ➥ Neither S1 nor S2 |
| iv ➥ Only S1 |
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| Q.25➡ | NTA UGC NET June 2018 Consider the following two Grammars : G1 : S → SbS|a G2 : S → aB|ab, A→GAB|a, B→ABb|b Which of the following option is correct ? |
| i➥ Only G1 is ambiguous |
| ii ➥ Only G2 is ambiguous |
| iii ➥ Both G1 and G2 are ambiguous |
| iv ➥ Both G1 and G2 are not ambiguous |
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| Q.26➡ | NTA UGC NET June 2018 A bottom-up parser generates: |
| i➥ Leftmost derivation in reverse |
| ii ➥ Right-most derivation in reverse |
| iii ➥ Left-most derivation |
| iv ➥ Right-most derivation |
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| Q.27➡ | NTA UGC NET November 2017 Paper 2 Which of the following statements is/are TRUE ? (i) The grammar S → SS | a is ambiguous (where S is the start symbol). (ii) The grammar S → 0S1 | 01S | e is ambiguous (the special symbol e represents the empty string and S is the start symbol). (iii) The grammar (where S is the start symbol). S → T/U T → x S y ? xy ? e U → yT generates a language consisting of the string yxxyy. |
| i➥ Only (i) and (ii) are TRUE |
| ii ➥ Only (i) and (iii) are TRUE |
| iii ➥ Only (ii) and (iii) are TRUE |
| iv ➥ All of (i), (ii) and (iii) are TRUE |
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| Q.28➡ | NTA UGC NET November 2017 Paper 2 A bottom-up parser generates: |
| i➥ Leftmost derivation in reverse |
| ii ➥ Right-most derivation in reverse |
| iii ➥ Left-most derivation |
| iv ➥ Right-most derivation |
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| Q.29➡ | NTA UGC NET November 2017 Paper 2 Match the description of several parts of a classic optimizing compiler in List – I, with the names of those parts in List – II:  |
| i➥ (a)-(iii), (b)-(iv), (c)-(ii), (d)-(i) |
| ii ➥ (a)-(iv), (b)-(iii), (c)-(ii), (d)-(i) |
| iii ➥ (a)-(ii), (b)-(iv), (c)-(i), (d)-(iii) |
| iv ➥ (a)-(ii), (b)-(iv), (c)-(iii), (d)-(i) |
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| Q.30➡ | NTA UGC NET January 2017 Paper 2 Consider the following statements related to compiler construction : I. Lexical Analysis is specified by context-free grammars and implemented by pushdown automata. II. Syntax Analysis is specified by regular expressions and implemented by finite-state machine. Which of the above statement(s) is/are correct ? |
| i➥ Only I |
| ii ➥ Only II |
| iii ➥ Both I and II |
| iv ➥ Neither I nor II |
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| Q.31➡ | NTA UGC NET August 2016 Paper 2 Which of the following is FALSE? |
| i➥ The grammar S→aS|aSbS|∈, where S is the only non-terminal symbol, and ∈ is the null string, is ambiguous. |
| ii ➥ An unambiguous grammar has same leftmost and rightmost derivation. |
| iii ➥ An ambiguous grammar can never be LR(k) for any k. |
| iv ➥ Recursive descent parser is a top-down parser |
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| Q.32➡ | NTA UGC NET August 2016 Paper 2 In compiler optimization, operator strength reduction uses mathematical identities to replace slow math operations with faster operations. Which of the following code replacements is an illustration of operator strength reduction ? |
| i➥ Replace P + P by 2 * P or Replace 3 + 4 by 7. |
| ii ➥ Replace P * 32 by P << 5 |
| iii ➥ Replace P * 0 by 0 |
| iv ➥ Replace (P << 4) – P by P * 15 |
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| Q.33➡ | NTA UGC NET August 2016 Paper 2 Which of the following are the principles tasks of the linker? I. Resolve external references among separately compiled program units. II. Translate assembly language to machine code. III. Relocate code and data relative to the beginning of the program. IV. Enforce access-control restrictions on system libraries |
| i➥ I and II |
| ii ➥ I and III |
| iii ➥ II and III |
| iv ➥ I and IV |
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| Q.34➡ | NTA UGC NET July 2016 Paper 2 In _____, the bodies of the two loops are merged together to form a single loop provided that they do not make any references to each other. |
| i➥ Loop unrolling |
| ii ➥ Strength reduction |
| iii ➥ Loop concatenation |
| iv ➥ Loop jamming |
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| Q.35➡ | NTA UGC NET July 2016 Paper 2 Which of the following is not typically a benefit of dynamic linking? I. Reduction in overall program execution time. II. Reduction in overall space consumption in memory. III. Reduction in overall space consumption on disk. IV. Reduction in the cost of software updates. |
| i➥ I and IV |
| ii ➥ I only |
| iii ➥ II and III |
| iv ➥ IV only |
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| Q.36➡ | NTA UGC NET July 2016 Paper 2 Which of the following is FALSE? |
| i➥ The grammar S → a Sb |bSa|SS|∈, where S is the only non-terminal symbol and ∈ is the null string, is ambiguous |
| ii ➥ SLR is powerful than LALR. |
| iii ➥ An LL(1) parser is a top-down parser. |
| iv ➥ YACC tool is an LALR(1) parser generator. |
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| Q.37➡ | NTA UGC NET December 2015 Paper 2 Loop unrolling is a code optimization technique |
| i➥ that avoids tests at every iteration of the loop. |
| ii ➥ that improves performance by decreasing the number of instructions in a basic block. |
| iii ➥ that exchanges inner loops with outer loops |
| iv ➥ that reorders operations to allow multiple computations to happen in parallel |
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| Q.38➡ | NTA UGC NET June 2015 Paper 3 Given the following grammars: G 1 : S → AB|aaB A → aA | ∈ B → bB | ∈ G2: S → A|B A → aAb | ab B → abB | ∈ Which of the following is correct? |
| i➥ G1 is ambiguous and G2 is unambiguous grammars |
| ii ➥ G1 is unambiguous and G2 is ambiguous grammars |
| iii ➥ Both G1 and G2 are ambiguous grammars |
| iv ➥ Both G1 and G2 are unambiguous grammars |
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| Q.39➡ | NTA UGC NET June 2015 Paper 2 Which one from the following is false? |
| i➥ LALR parser is Bottom up parser |
| ii ➥ A parsing algorithm which performs a left to right scanning and a right most deviation is RL (1) |
| iii ➥ LR parser is Bottom up parser. |
| iv ➥ In LL(1), the 1 indicates that there is a one – symbol look – ahead. |
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| Q.40➡ | NTA UGC NET June 2015 Paper 2 Which phase of compiler generates stream of atoms? |
| i➥ Syntax Analysis |
| ii ➥ Lexical Analysis |
| iii ➥ Code Generation |
| iv ➥ Code Optimization |
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