search
Log In
0 votes
339 views

 Describe the languages denoted by the following regular expressions:

  1. $a(a\mid b)^{\ast}a.$
  2. $((\epsilon\mid a)b^{\ast})^{\ast}.$
  3. $(a\mid b)^{\ast}a(a\mid b)(a\mid b).$
  4. $a^{\ast}ba^{\ast}ba^{\ast}ba^{\ast}.$
  5. $(aa\mid bb)^{\ast}((ab\mid ba)(aa\mid bb)^{\ast}(ab\mid ba)(aa\mid bb)^{\ast})^{\ast}.$
in Compiler Design 339 views

1 Answer

0 votes
a). start and end with a.

b). (a+b)* or we can say universal set on symbols (a,b).

c). end with aaa or aab or aba or abb.

d). containing exactly 3 b's.

e). m solving (i will post (e) asap.)

correct me if wrong..
1
can we describe c) as third last symbola a
0

@

e). even no of a’s and b’s.

Related questions

0 votes
0 answers
1
320 views
Most languages are case sensitive, so keywords can be written only one way, and the regular expressions describing their lexeme is very simple. However, some languages, like SQL, are case insensitive, so a keyword can be written either in lowercase or in ... regular expression for a keyword in a case-insensitive language. Illustrate the idea by writing the expression for "select" in SQL.
asked Aug 5, 2019 in Compiler Design Lakshman Patel RJIT 320 views
0 votes
0 answers
2
545 views
Write regular definitions for the following languages: All strings of lowercase letters that contain the five vowels in order. All strings of lowercase letters in which the letters are in ascending lexicographic order. Comments, consisting of a string surrounded by /* and */, without ... 's that do not contain the substring abb. All strings of a's and b's that do not contain the subsequence abb.
asked Aug 5, 2019 in Compiler Design Lakshman Patel RJIT 545 views
1 vote
1 answer
3
0 votes
0 answers
4
258 views
Consult the language reference manuals to determine the sets of characters that form the input alphabet (excluding those that may only appear in character strings or comments), the lexical form of numerical constants, and the lexical form of identifiers, for each of the following languages: C C++ C# Fortran Java Lisp SQL
asked Aug 5, 2019 in Compiler Design Lakshman Patel RJIT 258 views
...