Q79.Marks: +2.0UGC NET Paper 2: Computer Science 7th Dec 2023 Shift 2
Match List-I with List-II according to input to the compiler phase that process it:
List I
List II
A.
Syntax tree
I.
Code generator
B.
Intermediate representation
II.
Semantic analyzer
C.
Token stream
III.
Lexical analyze
D.
Character stream
IV.
Syntax analyzer
Choose the correct answer from the options given below :
1.A - IV, B - III, C - I, D - II
2.A - II, B - I, C - IV, D - III✓ Correct
3.A - II, B - IV, C - I, D - III
4.A - IV, B - I, C - II, D - III
Solution
The correct answer is A - II, B - I, C - IV, D - III
EXPLANATION:
List-I:
A. Syntax tree: This is a tree representation of the syntactic structure of source code according to the formal grammar of the programming language.
B. Intermediate representation: This is a less abstract computational syntax tree that is easier to compile into machine code.
C. Token stream: This is the output from the lexical analyzer. It's a sequence of standardized symbols representing language components (operators, identifiers, keywords, etc).
D. Character stream: This is the raw source code as input into the compiler.
List-II:
I. Code generator: This phase of the compiler reads the intermediate representation and transforms it into target machine code.
II. Semantic analyzer: The semantic analyzer uses the syntax tree to check the source code for semantic errors and gathers type information for the following code-generation phase.
III. Lexical analyzer: This phase of the compiler reads raw source code (character stream) and transforms it into a series of tokens (token stream).
IV. Syntax analyzer: Also known as a parser, this phase of the compiler reads the token stream from the lexical analyzer and groups the tokens into grammatically cohesive sections by constructing a syntax tree.
Process Flow:
The raw source code (Character stream) is read by the Lexical analyzer that turns it into a series of Tokens (Token stream). This corresponds to D - III.
The Syntax Analyzer or parser takes that Token stream and groups the tokens into hierarchically structured expressions to form a Syntax tree which follows the grammar rules of the language. This corresponds to C - IV.
The Semantic Analyzer will then inspect the Syntax tree to check the source code for semantic consistency with the language definition. This corresponds to A - II.
Finally, the Code generator takes the output from the Semantic Analyzer phase, usually an Intermediate representation, and transforms it into machine language instructions to get a final executable. This corresponds to B - I.
Hence, A-II, B-I, C-IV, and D-III is the correct relation.