Question
The lexical analysis for a modern computer language such as Java needs the power of which one of the following machine models in a necessary and sufficient sense?
Official answer and solution
- Official answer
- A
- From
- Official GATE 2011 answer key
Solution
Identify the language class of lexical tokens and the minimal automata model required to scan them.
- Tokens in programming languages like Java (keywords, identifiers, numeric literals, punctuation symbols) are described by regular expressions.
- Regular languages are accepted by finite state automata (DFA/NFA) and do not require auxiliary stack memory or tape storage.
- Thus, a finite state automaton is both necessary (regular expressions cannot be recognized by anything simpler) and sufficient to perform lexical analysis.
Final answer
A
The answer is the one in the official GATE answer key. The solution is this site's own explanation.
Source
- Paper
- GATE 2011 Computer Science and Information Technology (CS)
- Question
- 19 of 65, printed as CS Q.19
- Section
- Computer Science and Information Technology
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