Question

16. (Project p01 notes) What sequence of tokens is recognized by the regular expressions shown in...

16. (Project p01 notes) What sequence of tokens is recognized by the regular expressions shown in the figure below given the input string +123.1?
[+|-]?[0-9]+\.[0-9]*([E|e][+|-]?[0-9]+)?
[+|-]?[0-9]+
\.[0-9]+
“.”
[+|-]
[0-9]+
Figure 16.
a. 3 tokens as follows + 123 .1
b. 1 token as follows +123.1
c. 4 tokens as follows + 123 . 1
d. 2 tokens as follows +123 .1

0 0
Add a comment Improve this question Transcribed image text
Answer #1

[+|-]?[0-9]+\.[0-9]*([E|e][+|-]?[0-9]+)? matches +123.1

[+|-]?[0-9]+ matches  +123

\.[0-9]+ matches  .123

“.” matches "1"
[+|-] matches +
[0-9]+ matches 123

Add a comment
Know the answer?
Add Answer to:
16. (Project p01 notes) What sequence of tokens is recognized by the regular expressions shown in...
Your Answer:

Post as a guest

Your Name:

What's your source?

Earn Coins

Coins can be redeemed for fabulous gifts.

Not the answer you're looking for? Ask your own homework help question. Our experts will answer your question WITHIN MINUTES for Free.
Similar Homework Help Questions
  • Regular expressions, DFA, NFA, grammars, languages Regular Languages 4 4 1. Write English descriptions for the...

    Regular expressions, DFA, NFA, grammars, languages Regular Languages 4 4 1. Write English descriptions for the languages generated by the following regular expressions: (a) (01... 9|A|B|C|D|E|F)+(2X) (b) (ab)*(a|ble) 2. Write regular expressions for each of the following. (a) All strings of lowercase letters that begin and end in a. (b) All strings of digits that contain no leading zeros. (c) All strings of digits that represent even numbers. (d) Strings over the alphabet {a,b,c} with an even number of a's....

  • 4. Write regular expressions that match the descriptions given below. (10 P Description A sequence of...

    4. Write regular expressions that match the descriptions given below. (10 P Description A sequence of digits of any length that also contains the sequence of four letters "meow", in that order, anywhere in the Expression sequence. A sequence of zero or more x's and y's, OR zero or one z's. 3 The American word color, or the British spelling (colour). Your answer can NOT include an or. 4 A string that begins with an X and ends with an...

  • 3. Create a CFG describing regular expressions over the alphabet {0, 1}. You will need to quote the regular expression operators and the template given you has them quoted as terminals. We expect the...

    3. Create a CFG describing regular expressions over the alphabet {0, 1}. You will need to quote the regular expression operators and the template given you has them quoted as terminals. We expect the grammar to generate the following syntactic constructions: • Union via "|", for example, 0 1 "|" 1 should be in the language generated by the grammar • Intersection via "&", for example, 0 1 "&" 1 should be in the language • Concatenation: any nonempty sequence...

  • Preliminaries For this lab you will be working with regular expressions in Python. Various functions for...

    Preliminaries For this lab you will be working with regular expressions in Python. Various functions for working with regular expressions are available in the re module. Fortunately, Python makes it pretty easy to check if a string matches a particular pattern. At the top of the file we must import the re module: import re Then we can use the search() function to test whether a string matches a pattern. In the example below, the regular expression has been saved...

  • 1. (p. 2-3.) Which of the following is NOT a reason for studying concepts of programming...

    1. (p. 2-3.) Which of the following is NOT a reason for studying concepts of programming languages according to Sebesta? a. Increased capacity to express ideas. b. Improved background for choosing appropriate languages. c. Increased ability to design new languages. d. Increased ability to learn new languages. 2. (p. 5-6.) What programming language has dominated scientific computing over the past 50 years? a. FORTRAN b. ALGOL c. SNOBOL d. PL/I 3. (p. 6.) What programming language has dominated artificial intelligence...

  • Please Do it In Java: Objectives: To Java programming language To understand the lexical analysis phase...

    Please Do it In Java: Objectives: To Java programming language To understand the lexical analysis phase of program compilation Assignment: The first phase of compilation is called scanning or lexical analysis. This phase interprets the input program as a sequence of characters and produces a sequence of tokens, which will be used by the parser. Write a Java, program that implements a simple scanner for a source file given as a command-line argument. The format of the tokens is described...

  • If i could get any guidance on how to get this started it will be great....

    If i could get any guidance on how to get this started it will be great. My prof. literally just gave us the information below (which are literally just instructions) and I am unsure on how to get started. For this assignment we are going to create a function that reads an input stream and classifies it into “tokens” from a language that we define here. In this language we make the following rules: ● An identifier is a letter...

  • The first project involves modifying the attached lexical analyzer and the compilation listing ge...

    The first project involves modifying the attached lexical analyzer and the compilation listing generator code. You need to make the following modifications to the lexical analyzer, scanner.l: 1. A second type of comment should be added that begins with // and ends with the end of line. As with the existing comment, no token should be returned. 2. The definition for the identifiers should be modified so that underscores can be included, however, consecutive underscores, leading and trailing underscores should...

  • please Answer the following regular expressions questions(also do number 9) Q4 Choose the pattern that finds...

    please Answer the following regular expressions questions(also do number 9) Q4 Choose the pattern that finds all filenames in which the first letters of the filename are astA, followed by a digit, followed by the file extension .txt. 1) astA[[:digit:]]\.txt 2) astA[[0-9]].txt 3) astA.\.txt 4) astA[[:digit:]].txt Q5 What's the difference between [0-z]+ and \w+ ? 1) The first one accepts 0 and z and the other doesn't. 2) The first one doesn't allow for uppercase letters. 3) The first one...

  • Here is the code I have so far. I'm trying to figure out how to implement...

    Here is the code I have so far. I'm trying to figure out how to implement a boolean and use precedence. The 2nd expression should be 14 but it comes out as 28 so I'm definitely not understanding. #include <stack> #include <iostream> #include <string> using namespace std; // Function to find precedence of // operators. int precedence(char op) {    if (op == '+' || op == '-')        return 1;    if (op == '*' || op ==...

ADVERTISEMENT
Free Homework Help App
Download From Google Play
Scan Your Homework
to Get Instant Free Answers
Need Online Homework Help?
Ask a Question
Get Answers For Free
Most questions answered within 3 hours.
ADVERTISEMENT
ADVERTISEMENT