4 Lecture
CS402
Midterm & Final Term Short Notes
Equivalent Regular Expressions
Equivalent regular expressions are regular expressions that represent the same language or set of strings. In other words, they have the same pattern or rule for matching strings. These equivalent expressions may have different syntax or structu
Important Mcq's
Midterm & Finalterm Prepration
Past papers included
Download PDF
- Which of the following regular expressions is equivalent to "a|b|c"?
A) "abc"
B) "[a-c]"
C) "a+b+c+"
D) "(a|b|c)"
Answer: D) "(a|b|c)"
Which of the following regular expressions is equivalent to "ab(a|b)"?
A) "ab(a+b)"
B) "a(ba|bb)"
C) "(a|b)ab"
D) "a(ba|bb)"
Answer: A) "ab(a+b)*"
Which of the following regular expressions is equivalent to "ab"?
A) "(a+b)"
B) "(ab)"
C) "(a|b)"
D) "(a|b*)"
Answer: C) "(a|b)*"
Which of the following regular expressions is equivalent to "a(b|c)"?
A) "a|b|c"
B) "a(bc)"
C) "a+(b|c)"
D) "(a+b+c)"
Answer: B) "a(bc)*"
Which of the following regular expressions is equivalent to "(ab)c"?
A) "abc"
B) "(a|b)c"
C) "ab+c"
D) "a(b+c)*c"
Answer: A) "abc*"
Which of the following regular expressions is equivalent to "a(b|c)d|aef"?
A) "a(b|c|ef)d"
B) "a(b|c)(d|ef)"
C) "(ab|ac)d|aef"
D) "(ab|ac)(d|ef)"
Answer: C) "(ab|ac)d|aef"
Which of the following regular expressions is equivalent to "a+b+c+"?
A) "a|b|c"
B) "(a+b+c)"
C) "(a+b)(b+c)(c+a)"
D) "(abc)+"
Answer: B) "(a+b+c)*"
Which of the following regular expressions is equivalent to "(ab|cd)+e"?
A) "(a+b+c+d)e"
B) "(a+b)(c+d)*e"
C) "a(b+e)|(c+d)e"
D) "(ab+cd)e+"
Answer: C) "a(b+e)|(c+d)e"
Which of the following regular expressions is equivalent to "a(b+c)d"?
A) "a(b|c)+d"
B) "a(b+c)d+"
C) "(ab|ac)d"
D) "a(b+d)(c+d)"
Answer: A) "a(b|c)+d"
Which of the following regular expressions is equivalent to "a(b+c)|d(e+f)"?
A) "(ab+ac)|(de+df)"
B) "a(b+c)d|d(e+f)"
C) "ab+def*"
D) "(a+b)(c+d)(e+f)*"
Answer: B) "a(b+c)d|d(e+f)"
Subjective Short Notes
Midterm & Finalterm Prepration
Past papers included
Download PDF
What are equivalent regular expressions? Answer: Equivalent regular expressions are regular expressions that represent the same language or set of strings. They may have different syntax or structure, but they match the same set of strings. Why is it important to identify equivalent regular expressions? Answer: Identifying equivalent regular expressions is important for optimization and simplification of regular expressions used in programming and text processing. How can you check if two regular expressions are equivalent? Answer: One way to check if two regular expressions are equivalent is to compare the languages or sets of strings they match. If they match the same set of strings, then they are equivalent. What is the difference between "a|b" and "[ab]"? Answer: "a|b" matches either "a" or "b", while "[ab]" matches any single character that is either "a" or "b". How can you simplify the regular expression "a(a|b)"? Answer: The regular expression "a(a|b)" can be simplified to "a*" since "a|b" matches any single character that is either "a" or "b". What is the equivalent regular expression of "ab"? Answer: The equivalent regular expression of "ab" is "(a|b)*". How can you simplify the regular expression "(ab|ba)"? Answer: The regular expression "(ab|ba)" can be simplified to "ab|ba" since it already has the simplest form. What is the difference between "(ab)" and "ab*"? Answer: "(ab)" matches any sequence of zero or more occurrences of the string "ab", while "ab*" matches any sequence of zero or more occurrences of the characters "a" and "b" in any order. How can you simplify the regular expression "(a|b)a(a|b)"? Answer: The regular expression "(a|b)a(a|b)" can be simplified to "(a|b)a" since the "(a|b)" before and after the "a" match the same set of strings. What is the equivalent regular expression of "a(b|c)*d"? Answer: The equivalent regular expression of "a(b|c)d" is "a(b|c)+d" since the "" after "(b|c)" can be replaced with a "+" to match one or more occurrences.