Question 1

Consider the following translation scheme. S ? ER R ? *E{print("*");}R | ? E? F + E {print("+");} | F F ? (S) | id {print(id.value);} Here id is a token that represents an integer and id.value represents the corresponding integer value. For an input '2 * 3 + 4', this translation scheme prints
A)2 * 3 + 4
B)2 * +3 4
C)2 3 * 4 +
D)2 3 4+*

Accepted Answer

The answer of Consider the following translation scheme. S ?...

Question 2

The grammar A ? AA | (A) | ? is not suitable for predictive-parsing because the grammar is
A)ambiguous
B)left-recursive
C)right-recursive
D)an operator-grammar

Accepted Answer

The answer of The grammar A ? AA | (A)...

Question 3

Consider the grammar S ? (S) | a Let the number of states in SLR(1), LR(1) and LALR(1) parsers for the grammar be n₁, n₂ and n₃ respectively. The following relationship holds good A) n₁ < n₂ < n₃ B) n₁ = n₃ < n₂ C) n₁ = n₂ = n₃ D) n₁ ? n₃ ? n₂

Accepted Answer

LR(1) parsers typically have more states than SLR(1) and LALR(1) parsers because they are more powerful and can handle more complex grammars by considering more lookahead information. LALR(1) parsers merge some of the states that are distinct in LR(1) parsers, leading to a smaller number of states than LR(1) but typically the same number as SLR(1) for many grammars.

Question 4

Consider the following expression grammar. The seman-tic rules for expressioncalculation are stated next to each grammar production.
E ? number E.val = number. val
| E '+' E E(1).val = E(2).val + E(3).val
| E '×' E E(1).val = E(2).val × E(3).val
The above grammar and the semantic rules are fed to a yacc tool (which is an LALR (1)parser generator) for parsing and evaluating arithmetic expressions. Which one of thefollowing is true about the action of yacc for the given grammar?
A)It detects recursion and eliminates recursion
B)It detects reduce-reduce conflict, and resolves
C)It detects shift-reduce conflict, and resolves the conflict in favor of a shift over a reduce action
D)It detects shift-reduce conflict, and resolves the conflict in favor of a reduce over a shift action

Accepted Answer

Yacc, being an LALR(1) parser generator, can detect shift-reduce conflicts in grammars. When such a conflict occurs, yacc defaults to a shift action over a reduce action as part of its conflict resolution strategy.

Quiz 3: Compiler Construction and Parsing Algorithms

Consider the following translation scheme. S ? ER R ? E{print("") ;}R | ? E? F + E {print("+") ;} | F F ? (S) | id {print(id.value) ;} Here id is a token that represents an integer and id.value represents the corresponding integer value. For an input '2 * 3 + 4', this translation scheme prints

The grammar A ? AA | (A) | ? is not suitable for predictive-parsing because the grammar is

Consider the grammar S ? (S) | a Let the number of states in SLR(1) , LR(1) and LALR(1) parsers for the grammar be n₁, n₂ and n₃ respectively. The following relationship holds good

Quiz 3: Compiler Construction and Parsing Algorithms

Consider the following translation scheme. S ? ER R ? *E{print("*") ;}R | ? E? F + E {print("+") ;} | F F ? (S) | id {print(id.value) ;} Here id is a token that represents an integer and id.value represents the corresponding integer value. For an input '2 * 3 + 4', this translation scheme prints

The grammar A ? AA | (A) | ? is not suitable for predictive-parsing because the grammar is

Consider the grammar S ? (S) | a Let the number of states in SLR(1) , LR(1) and LALR(1) parsers for the grammar be n1, n2 and n3 respectively. The following relationship holds good

Consider the following translation scheme. S ? ER R ? E{print("") ;}R | ? E? F + E {print("+") ;} | F F ? (S) | id {print(id.value) ;} Here id is a token that represents an integer and id.value represents the corresponding integer value. For an input '2 * 3 + 4', this translation scheme prints

Consider the grammar S ? (S) | a Let the number of states in SLR(1) , LR(1) and LALR(1) parsers for the grammar be n₁, n₂ and n₃ respectively. The following relationship holds good