Regular Expressions

1) What is the significance of Matcher class for regular expression in java?

interpretest both pattern and performs match operations in the string
interpretes pattern in the string
Performs match in the string
None of the mentioned

2) Which capturing group can represent the entire expression?

group *
group 0
group * or group 0
None of the mentioned

3) What does public int end(int group) return?

offset from last character of the subsequent group
offset from first character of the subsequent group
offset from last character matched
offset from first character matched

4) Which of the following identity is wrong?

R + R = R
(R*)* = R*
Both A and B
(phi)R = R(phi) = RR*

5) Which of the following is not a class of java.util.regex?

Pattern class
matcher class
PatternSyntaxException
Regex class

6) Regular expressions are used to represent which language

Recursive language
Context free language
Regular language
All of these

7) The set of all strings over Sigma = {a,b} in which all strings having bbbb as substring is:

(a+b)* bbbb (a+b)*
(a+b)* bb (a+b)*bb
bbbb (a+b)*
bb (a+b)*

8) What does public int start() return?

returns start index of the input string
returns start index of the current match
returns start index of the previous match
none of the mentioned

9) Which of the following statements about the regex API are true?

Instances of the Pattern class are used to match character sequences against a given pattern
The package java.util.regex includes an exception called PatternSyntaxException
Instances of Matcher class are used to represent regular expressions in the form of String type
None of the above

10) What are the main methods of Java Regex?

matches
lookingAt
find
All of the above

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