Question

Problem 5 Regular Expressions.

a) Define a regular expression for all strings of odd length,
over the alphabet of {0}.

b) Define a regular expression for identifiers over the
alphabet of {A,B,C,a,b,c,0,1,2,3,4,5,6,7,8,9}, such

that an identifier must begin with an alphabetic character and
must contain at least one numeric character.

c) Try to modify the definition above so that identifiers
still begin with an alphabetic character, but after

that, it must contain at least one numeric, at least one
lower-case letter, and at least one upper-case letter,

but no restrictions on where they can/must occur.

Answer #1

**Answer for
(a):**

The regular expression for all strings of odd length, over the
alphabet of {0} is: **(00) ^{*}0**

**Answer for
(b):**

The regular expression for identifiers over the alphabet of {A,B,C,a,b,c,0,1,2,3,4,5,6,7,8,9}, such that an identifier must begin with an alphabetic character and must contain at least one numeric character is :

**(A+B+C+a+b+c)
(A+B+C+a+b+c) ^{*} (0+1+2+3+4+5+6+7+8+9)**

**(A+B+C+a+b+c+0++1+2+3+4+5+6+7+8+9) ^{*}**

**Answer for
(C):**

**X ->** **A+B+C+a+b+c**

**N -> 0+1+2+3+4+5+6+7+8+9**

**Y -> A+B+C**

**Z -> a+b+c**

The regular expression is : **X(N+Y+Z) (X+N) ^{*} (N+Y+Z)
(X+N)^{*} (Y+N+Z) (X+N)^{*}**

Find a regular expression to describe:
The set of all strings over the alphabet {a, b, c, d}
that contain exactly one a and exactly one b
So, for example, the following strings are in this
language:
ab, ba, cccbad, acbd, cabddddd, ddbdddacccc
and the following strings are NOT in this
language:
a, ccbc, acbcaaacba, acacac, bcbbbbbca, aca, c, d,
b

Show a regular expression representing the described set:
a). The set of strings of odd length over {s,t,r,i,n,g}
containing exactly 3 n's.

Write the regular expression for the following sets (4.5)
4.1 All strings over {a,b} that are odd in
length
4.2 All strings over {a,b} whose length is
not a multiple of 3
4.3 All strings over a,b that start with
aa and end with bb

Question 4
Write a regular expression that generates each of the following
language constructs:
(1) String constants with the following specifications:
A string constant consists of any sequence of characters
enclosed by the quotation marks: “ and ”
The sequence may be
empty.
The sequence cannot span
multiple lines.
Don’t worry about escape
characters (assume that they won’t appear in the input).
(2) Multiple-line comment in C, C++ and JAVA with the
following specifications:
The comment consists
of any sequence...

Which one of the following languages over the alphabet {0,1} is
described by the regular expression
(0+1)* 0 (0+1)* 0 (0+1)* ?
a.The set of all strings that begin and end with either 0 or
1
b.The set of all strings containing at most two zeros
c.The set of all strings containing at least two zeros.
d.The set of all strings containing the substring 00

1.2 Which of the following statements is
wrong?
a). A set is a
subset of itself
b). Emptyset
is a subset of any set
c). A set is a
subset of its powerset
d). The
cardinality of emptyset is 0
1.3. Which of the following statements is
correct?
a). A string
is a set of symbols from an alphabet
b). The length
of the concatenation of two strings can
be
the same as one of them
c). The length
of...

3. Write function, leastChar(inputString) that takes as input a
string of one or more letters (and no other characters) and prints
1) the "least" character in the string, where one character is less
than another if it occurs earlier in the alphabet (thus 'a' is less
than 'C' and both are less than 'y') and 2) the index of the first
occurrence of that character. When comparing letters in this
problem, ignore case - i.e. 'e' and 'E' should be...

4. The _____ case is performed by the switch statement
if a match is not found
default
first
second
otherwise
Answer:
5. When three relational expressions are joined by OR
(||) operators, there must be at least _____ of the relational
expressions that evaluate to true for the logical expression to
evaluate to true.
one
two
three
none of the relational expressions evaluate to
true
Answer:
6. Which of the following items is an acceptable first
character in a Java...

1. (4 pts) Consider all bit strings of length six. a) How many
begin with 01? b) How many begin with 01 and end with 10? c) How
many begin with 01 or end with 10? d) How many have exactly three
1’s? 2. (8 pts) Suppose that a “word” is any string of six letters.
Repeated letters are allowed. For our purposes, vowels are the
letters a, e, i, o, and u. a) How many words are there? b)...

***Programming language is Java. After looking at this scenario
please look over the requirements at the bottom (in bold)
THIS IS ALL THAT WAS PROVIDED. PLEASE
SPECIFY ANY QUESTIONS IF THIS IS NOT CLEAR (don't just say more
info, be specific)***
GMU in partnership with a local sports camp is offering a
swimming camp for ages 10-18. GMU plans to make it a regular event,
possibly once a quarter. You have been tasked to create an
object-oriented solution to register,...

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