CS606 Midterm Past Papers by Sadaf Awan

CS606 · Midterm MCQ · By Sadaf Awan · BSCS

1: An ----- does not need to examine the entire stack for a handle, the state symbol on the top of the stack contains all the information it needs

LR parser

RL parser BU parser None of the giv

2: Yacc contains built-in support for handling ambiguous grammars resulting in shift-reduce conflicts. By default these conflicts are solved by performing the ________.

Shift action

Reduce action Shift and reduce actions De-allocation of memory

3: S --> A | xb A --> aAb | x This grammar contains a reduce-reduce conflict

True

False

4: S --> a | B B --> Bb | E The non-terminal _______ is left recursive.

B

A E

5: When generating a lexical analyzer from a ________ description, the item sets (states) are constructed by two types of “moves”: character moves and e moves. Character Grammar

Token (Page 18)

Sentence

6: Left factoring is enough to make a grammar LL(1). True

False

7: S --> A B A --> e | aA B --> e | bB FIRST(S) contains ___ elements.

7: Grammars with LL(1) conflicts can be made LL(1) by applying left-factoring, substitution, and left-recursion removal. Left-factoring takes care of ________conflicts. FIRST/FIRST FIRST/SECOND SECOND/FIRST

8: Alternative of the backtrack in parser is Look ahead symbol in _________ .

Input (Page 46)

Output Input and Output

9: Typical compilation means programs written in high-level languages to low-level

Object code (page 2)

Byted code Unicode Both Object Code and byte code

10: In PASCAL ___________ represent the inequality test.

11: LR parsing ______________ a string to the start symbol by inverting productions.

Reduces (Page 63)

Shifts Adds 12: In parser the two LL stand(s) for ____________ . Left-to-right scan of input left-most derivation

13: Parser always gives a tree like structure as output

True (Page 37)

False

14: Lexer and scanner are two different phases of compiler True

15: In compilation process Hierarchical analysis is also called----------- Parsing

Both Parsing and Syntax analysis

16: Ambiguity can easily be handled by Top-down Parser Select correct option:

False

17: Front-end of a two pass compiler is consists of Scanner.

True (Page 5)

False

18: LL(1) parsing is called non-predictive parsing.

False

19: In predictive parsing table the rows are ____________________ .

Non-terminals (Page 54)

Terminals Both non-terminal and terminals

20: In LL1() parsing algorithm _________ contains a sequence of grammar symbols.

Stack (Page 55)

Link list Array None