MCQOPTIONS
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MCQOPTIONS
This section includes 17 Mcqs, each offering curated multiple-choice questions to sharpen your Compilers knowledge and support exam preparation. Choose a topic below to get started.
| 1. |
Given the following expression grammar :E → E ⋆ F | F + E | FF→ F - F| idWhich of the following is true? |
| A. | ⋆ has higher precedence than + |
| B. | - has higher precedence than ⋆ |
| C. | + and - have same precedence |
| D. | + has higher precedence than ⋆ |
| Answer» C. + and - have same precedence | |
| 2. |
Consider the following grammarS → m | mn | mnoChoose correct statement from the following: |
| A. | The grammar is LL (2) |
| B. | The grammar is LL (4) |
| C. | The grammar is LL (1) |
| D. | The grammar is LL (3) |
| Answer» E. | |
| 3. |
Consider the following Syntax Directed Translation Scheme (SDTS), with non-terminals {S, A} and terminals {a, b}.S → aA {print 1}S → a {print 2}A → Sb {print 3}Using the above SDTS, the output printed by a bottom-up parser, for the input aab is: |
| A. | 1 3 2 |
| B. | 2 2 3 |
| C. | 2 3 1 |
| D. | syntax error |
| Answer» D. syntax error | |
| 4. |
Consider the following statements.S1 : Every SLR(1) grammar is unambiguous but there are certain unambiguous grammars that are not SLR(1).S2 : For any context-free grammar, there is a parser that takes at most O(n3) time to parse a string of length n.Which one of the following option is correct? |
| A. | S1 is true and S2 is false |
| B. | S1 is false and S2 is true |
| C. | S1 is true and S2 is true |
| D. | S1 is false and S2 is false |
| Answer» D. S1 is false and S2 is false | |
| 5. |
Consider the following two sets of LR(1) items of an LR(1) grammar.X → c.X, c/d X → c.X, $X → .cX, c/d X → .cX, $X → .x, c/d X → .d, $Which of the following statements related to merging of the two sets in the corresponding LALRparser is/are FALSE?1. Cannot be merged since look aheads are different.2. Can be merged but will result in S-R conflict.3. Can be merged but will result in R-R conflict.4. Cannot be merged since goto on c will lead to two different sets. |
| A. | 1 only |
| B. | 2 only |
| C. | 1 and 4 only |
| D. | 1, 2, 3 and 4 |
| Answer» E. | |
| 6. |
Among simple LR (SLR), canonical LR, and look – ahead LR (LALR), which of the following pairs identify the method that is very easy to implement and the method that is the most powerful, in that order? |
| A. | SLR, LALR |
| B. | Canonical LR, LALR |
| C. | SLR, canonical LR |
| D. | LALR, canonical LR |
| Answer» D. LALR, canonical LR | |
| 7. |
In LR(k) parsing, when the value of k is omitted, it is assumed to be ______. |
| A. | 1 |
| B. | 2 |
| C. | 3 |
| D. | 8 |
| Answer» B. 2 | |
| 8. |
A top-down parser generates |
| A. | Rightmost derivation |
| B. | Rightmost derivation in reverse |
| C. | Leftmost derivation |
| D. | Leftmost derivation in reverse |
| Answer» D. Leftmost derivation in reverse | |
| 9. |
Match the following:(P)Lexical analysis(i)Leftmost derivation(Q)Top down parsing(ii)Type checking(R)Semantic analysis(iii)Regular expressions(S)Runtime environments(iv)Activation records |
| A. | P – i, Q – ii, R – iv, S - iii |
| B. | P – iii, Q – i, R – ii, S - iv |
| C. | P – ii, Q – iii, R – I, S - iv |
| D. | P – iv, Q – I, R – ii, S - iii |
| Answer» C. P – ii, Q – iii, R – I, S - iv | |
| 10. |
Assume that the SLR parser for a grammar G has n1 states and the LALR parser for G has n2 states. The relationship between n1 and n2 is : |
| A. | n1 is necessarily less than n2 |
| B. | n1 is necessarily equal to n2 |
| C. | n1 is necessarily greater than n2 |
| D. | none of the options |
| Answer» C. n1 is necessarily greater than n2 | |
| 11. |
Consider the following parse tree for the expression a # b $ c $ d # e # f, involving two binary operators $ and #.Which one of the following is correct for the given parse tree? |
| A. | $ has higher precedence and is left associative; # is right associative. |
| B. | # has higher precedence and is left associative; $ is right associative |
| C. | $ has higher precedence and is left associative; # is left associative |
| D. | # has higher precedence and is right associative; $ is left associative |
| Answer» B. # has higher precedence and is left associative; $ is right associative | |
| 12. |
Consider the following grammar GS → F | HF → p | cH → d | cWhere S, F, and H are non-terminal symbols, p, d, and c are terminal symbols. Which of the following statement(s) is/are correct?S1. LL(1) can parse all strings that are generated using grammar GS2. LR(1) can parse all string that are generated using grammar G |
| A. | Only S1 |
| B. | Only S2 |
| C. | Both S1 and S2 |
| D. | Neither S1 nor S2 |
| Answer» E. | |
| 13. |
Consider the following context-free grammar where the set of terminals is {a, b, c, d, f}.S → d a T | R fT → a S | b a T | ϵR → c a T R | ϵThe 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. | (1) S → R f (2) S → R f (3) T → ϵ (4) T → ϵ |
| B. | (1) blank (2) S → R f (3) blank (4) blank |
| C. | (1) S → R f (2) blank (3) blank (4) T → ϵ |
| D. | (1) blank (2) S → R f (3) T → ϵ (4) T → ϵ |
| Answer» B. (1) blank (2) S → R f (3) blank (4) blank | |
| 14. |
A canonical set of items is given belowS → L. > RQ → R.On input symbol < the set has |
| A. | a shift-reduce conflict and a reduce-reduce conflict |
| B. | a shift-reduce conflict but not a reduce-reduce conflict |
| C. | a reduce-reduce conflict but not a shift-reduce conflict. |
| D. | neither a shift-reduce nor a reduce-reduce conflict |
| Answer» E. | |
| 15. |
UNIFORM_SYMBOL_TABLE?$ |
| A. | Has all constants in the program |
| B. | Permanent table of rules in the form of patterns for matching with the uniform symbol table to discover syntactic structure |
| C. | Consists of full or partial list of the tokens as they appear in the program created by Lexical analysis and used for syntax analysis and interpretation |
| D. | A permanent table which has all key words and special symbols of the language in symbolic form |
| Answer» D. A permanent table which has all key words and special symbols of the language in symbolic form | |
| 16. |
Assembler_is_a_program_that$ |
| A. | Puts programs into memory and executes them |
| B. | Translates the assembly language into machine language |
| C. | Writes in high level language and produces an object program |
| D. | None of the mentioned |
| Answer» C. Writes in high level language and produces an object program | |
| 17. |
Advantage of incorporating the macro-processor into pass 1 is that |
| A. | Many functions have to be implemented twice |
| B. | Functions are combined not necessarily creating intermediate files as output from the macro-processor and input to the assembler |
| C. | More flexibility is provided to the programmer in that he may use all the features of the assembler in conjunction with macros |
| D. | All of the mentioned |
| Answer» E. | |