1
The first phase of a compiler is
Correct Answer
lexical analysis
☑ MCQ PRACTICE
Compiler Design Unit 1
Practice objective questions for quick revision and examination preparation. Try answering each question before revealing the answer.
Compiler Design MCQs - Unit 1
2
The output of the lexical analyzer is a stream of
Correct Answer
tokens
3
The output of the syntax analyzer (parser) is a
Correct Answer
parse tree (syntax tree)
4
Type checking is performed during
Correct Answer
semantic analysis
5
Three-address code is an example of
Correct Answer
intermediate representation
6
The symbol table is used to
Correct Answer
store information about identifiers such as name, type and scope
7
A compiler differs from an interpreter in that a compiler
Correct Answer
translates the whole source program into a target program
8
Which of the following belongs to the back end of a compiler?
Correct Answer
Code generation
9
A sequence of characters in the source program that matches the pattern for a token is called a
Correct Answer
lexeme
10
A description of the form that the lexemes of a token may take is called a
Correct Answer
pattern
11
Besides producing tokens, the lexical analyzer also removes
Correct Answer
white space and comments
12
In input buffering, a sentinel is used to
Correct Answer
reduce the number of tests needed to detect the end of the buffer
13
Lex is a tool used to generate
Correct Answer
lexical analyzers
14
A Lex program consists of how many sections separated by %%?
Correct Answer
three (declarations, translation rules, auxiliary functions)
15
The regular expression (a|b)* denotes
Correct Answer
all strings of a's and b's, including the empty string
16
A DFA differs from an NFA in that a DFA has
Correct Answer
exactly one transition for each input symbol from each state
17
An NFA may contain
Correct Answer
ε-transitions and multiple transitions on the same symbol
18
The algorithm used to convert an NFA into a DFA is
Correct Answer
subset construction
19
The algorithm used to convert a regular expression into an NFA is
Correct Answer
Thompson's construction
20
DFA minimization is done to
Correct Answer
reduce the number of states
21
To build a DFA directly from a regular expression, which function is used?
Correct Answer
followpos
22
The ε-closure of a state is the set of states
Correct Answer
reachable from it using ε-transitions only
23
Which of the following is detected as a lexical error?
Correct Answer
An illegal character in the source program
24
The number of tokens in the statement int a = b + 1; is
Correct Answer
7
25
Scope that is determined at compile time from the structure of the program text is called
Correct Answer
static (lexical) scope
Fill in the Blanks
26
The first phase of a compiler is ______ analysis.
Correct Answer
lexical
27
A sequence of characters in the source program that matches the pattern of a token is called a ______.
Correct Answer
lexeme
28
______ is a tool that generates lexical analyzers.
Correct Answer
Lex
29
An NFA is converted into a DFA using the ______ construction.
Correct Answer
subset
30
A regular expression is converted into an NFA using ______ construction.
Correct Answer
Thompson's
31
The ______ of a state is the set of states reachable from it using only ε-transitions.
Correct Answer
ε-closure
32
The ______ table stores information about the identifiers in the source program.
Correct Answer
symbol
33
In input buffering, a ______ character marks the end of a buffer.
Correct Answer
sentinel
34
The lexical analyzer reads the ______ program and produces a stream of tokens.
Correct Answer
source
35
DFA minimization reduces the number of ______.
Correct Answer
states
36
The output of the lexical analyzer is a stream of ______.
Correct Answer
tokens
37
A compiler that runs on one machine and produces code for a different machine is called a ______ compiler.
Correct Answer
cross
38
The analysis part (front end) of a compiler is independent of the ______ machine.
Correct Answer
target
39
An ______ translates and executes the source program statement by statement.
Correct Answer
interpreter
40
Scope that is determined from the program text at compile time is called ______ scope.
Correct Answer
static (lexical)