Is ambiguous grammar context free Mcq?

Is ambiguous grammar context free Mcq?

Is ambiguous grammar context free Mcq?

Automata Theory Questions and Answers – Ambiguous Grammar This set of Automata Theory Multiple Choice Questions & Answers (MCQs) focuses on “Ambiguous Grammar”. Explanation: A context free grammar is ambiguous if it has more than one parse tree generated or more than one leftmost derivations.

What is meant by ambiguity in context free grammar?

Advertisements. If a context free grammar G has more than one derivation tree for some string w ∈ L(G), it is called an ambiguous grammar. There exist multiple right-most or left-most derivations for some string generated from that grammar.

How do you prove that a context free grammar is ambiguous?

3 Answers

  1. All CFG without useless symbols and with left and rigth recursion for the same symbol, is ambiguous. In general: ...
  2. To probe ambiguity, you must find 2 Leftmost Derivations for the same string (or 2 rightmost derivations, or 2 derivation trees).

Which type of grammar is context free?

Chomsky Classification of Grammars
Grammar TypeGrammar AcceptedLanguage Accepted
Type 0Unrestricted grammarRecursively enumerable language
Type 1Context-sensitive grammarContext-sensitive language
Type 2Context-free grammarContext-free language
Type 3Regular grammarRegular language

How do you determine ambiguity?

A grammar is said to be ambiguous if there exists more than one leftmost derivation or more than one rightmost derivation or more than one parse tree for the given input string. If the grammar is not ambiguous, then it is called unambiguous. If the grammar has ambiguity, then it is not good for compiler construction.

Which language is accepted by finite automata?

Alternatively, a regular language can be defined as a language recognized by a finite automaton. The equivalence of regular expressions and finite automata is known as Kleene's theorem (after American mathematician Stephen Cole Kleene).

Is CNF ambiguous?

No, it is not: there are context-free languages that are inherently ambiguous, meaning that they have no unambiguous grammar.

What is ambiguity in grammar explain with example?

Definition: G = (V,T,P,S) is a CFG is said to be ambiguous if and only if there exist a string in T* that has more than on parse tree. ... Both the above parse trees are derived from same grammar rules but both parse trees are different. Hence the grammar is ambiguous.

How do you remove ambiguity in grammar?

Methods To Remove Ambiguity-

  1. By fixing the grammar.
  2. By adding grouping rules.
  3. By using semantics and choosing the parse that makes the most sense.
  4. By adding the precedence rules or other context sensitive parsing rules.

What do you say a grammar is ambiguous?

In computer science, an ambiguous grammar is a context-free grammar for which there exists a string that can have more than one leftmost derivation or parse tree, while an unambiguous grammar is a context-free grammar for which every valid string has a unique leftmost derivation or parse tree.

Which is an ambiguous grammar in context free grammar?

Explanation: A context free grammar is ambiguous if it has more than one parse tree generated or more than one leftmost derivations. An unambiguous grammar is a context free grammar for which every valid string has a unique leftmost derivation. 2. Which of the following are always unambiguous?

When is a context free language inherently ambiguous?

Ambiguous Context Free Languages: A context free language is called ambiguous if there is no unambiguous grammar to define that language and it is also called inherently ambiguous Context Free Languages. Note: If a context free grammar G is ambiguous, language generated by grammar L(G) may or may not be ambiguous.

Which is true in context free grammar and context free languages?

(B) is also correct as unambiguous CFG has a unique parse tree for each string of the language generated by it. (C) is false as some languages are accepted by Non- deterministic PDA but not by deterministic PDA. (D) is also true as finite set of string is always regular.

When is a grammar ambiguous in a parse tree?

Explanation: A context free grammar is ambiguous if it has more than one parse tree generated or more than one leftmost derivations. An unambiguous grammar is a context free grammar for which every valid string has a unique leftmost derivation.


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