I am doing exercises which has to do with the area of regular pentagon.
(Geometry: area of a regular polygon) A regular polygon is an n-sided polygon in which all sides are of the same length and all angles have the same degree (i.e., the polygon is both equilateral and equiangular). The formula for computing the area of a regular polygon is :
I have checked errata on their page and they did not list the type-o under the final result.
Errata link [URL] ....
their result is
Enter the number of sides: 5
Enter the side: 6.5
The area of the polygon is 74.69017017488385
and mine is Area of regular pentagon is 72.69017017488385
is it a code error?
import java.util.Scanner;
public class AreaOfAregularPolygon4_5 {
public static void main (String[] args){
//Initiate scanner and use the input
Scanner input = new Scanner (System.in);
System.out.println(" Enter the number of sides in polygon");
I have to produce a program that gives the area of a pentagon. I'm very new to java so I get confused easily. I followed the formula in the textbook but I'm doing something wrong and I don't know what. This is the code I've written.
[import java.util.Scanner; public class Pentagon { public static void main(String[]args) { Scanner input = new Scanner (System.in); // Prompt for length
Write a Java program that calculates the area and volume of a cube, sphere, cylinder, and regular tetrahedron. Your program should obtain the necessary input for each of the objects from the console and output the input, area, and volume of the object. Use appropriate messages to guide the user of your program.
(Corner point coordinates) Suppose a pentagon is centered at (0, 0) with one point at the 0 o’clock position. Write a program that prompts the user to enter the radius of the bounding circle of a pentagon and displays the coordinates of the five corner points on the pentagon. Here is a sample run:
Enter the radius of the bounding circle: 100 The coordinates of five points on the pentagon are (95.1057, 30.9017) (0.000132679, 100) (-95.1056, 30.9019) (-58.7788, -80.9015) (58.7782, -80.902)
What we know , we know both the radius of the circle(user inputted) and the side of the pentagon from formula (double side = 2 * radius * Math.sin(Math.PI/5)) .We also know that one point is (0 .100) Also i know that the distance between 2 points is Math.sqrt(Math.pow(x1 - x2 ,2) - Math.pow(y1 -y2 ,2)) .
There might be other ways to solve it but this is my best bet trough i dont remember how to solve linear equations of the form x^2 + y^2 = - radius and radius ^2 = x^2 + (y - 100) ^ 2..
The solution i found is using the radius from the center to the point we want to find out and using the radius to the point we already know ( 0 .100) but i have to solve that damn equation first ...
I'm working on is to create a program to display an n-sided regular polygon and uses two buttons named +1 and -1 to increase or decrease the size of the polygon. Also enable the the user to increase or decrease the size by clicking the right or left mouse button and by pressing the UP and DOWN arrow keys. So, first off I'm just trying to figure out how to display an n-sided polygon. I have some of the other components started, but I'm just trying to focus on getting this to work.
I am currently enrolled in my first Java class. I have taken C# in the past so I've messed with some regular expressions, but I am having trouble finding a good website for Java. Is the syntax the same?I want to create a regular expression to only allow the following characters: c C f F [and any 1-3 digit number].
Prompt user to enter a social security number in the format DDD-DD-DDDD, where D is a digit. Displays "Valid SSN" for a correct ssn, and "Invalid SSN" otherwise.I have it working I am just looking for other ways to solve this with an array maybe or something simpler. I have used if statements here:
public static boolean checkSSN(String social) { boolean valid = false; // 9 digits and 2 hyphens. First three characters, 5 and 6, and 8, 9, // 10, 11 are digits
I have a string "We have 7 tutorials for Java, 2 tutorials for Javascript and 1 tutorial for Oracle" I need to replace the numbers based on the below condition.
if more then 5, replace with many if less then 5, replace with a few if it is 1, replace with "only one"
below is my code, I am missing the equating part to replace the numbers
private static String REGEX="(d+)"; private static String INPUT="We have 7 tutorials for Java, 2 tutorials for Javascript and 1 tutorial for Oracle"; //String pattern= "(.*)(d+)(.*)"; private static String REPLACE = "replace with many"; public static void main(String[] args) { // Create a Pattern object
I have some problems about performing regular expression. In the following code, the output as a result is being "valid last name". But in my opinion, it should be "invalid last name". Because "Doe" has not any space, apostroph or any hypen. Look at the regular expression statement: "[a-zA-Z]+([ '-][a-zA-Z]+)*"
package deneme; public class Deneme { public static void main(String[] args) { String lastName = "Mc-Something"; // Mc-Something if(!lastName.matches("[a-zA-Z]+([ '-][a-zA-Z]+)*")) System.out.println("Invalid last name"); else System.out.println("Valid last name"); } }
I know that the asterisk qualifier means character(s) in any number.(Is this wrong?) So for "Mc-Something", 'M' corresponds to [a-zA-Z], 'c' corresponds to +, - corresponds to [ '-], 'S' corresponds to [a-zA-Z], "o" corresponds to +, and finally "mething" corresponds to *, doesn't they? But for "Doe", there is no any space, apostroph or hypen.
I know that for a binary search tree the insert() method is easy. You just kept comparing the values of the nodes, and you would know whether to go left or right depending on the value of the node.However, I am stumped when trying to figure out how to add a node into a normal binary tree where you just keep adding the nodes to the leftmost side, regardless of value.Here is my attempt at the insert() method:
public class RegularTree extends BinaryTree { public CompleteTree() { super(); }
public void insert(Comparable item) { if(this.isEmpty()) { this.setRoot(new TreeNode(item)); return;
From this, I need to extract the statements of variables that do not start with _G . I mean, I need to extract, Y in 1..15 , __X in 1..15 /17/20 but not _G7145 in 10..15 / 16.
I am using regular Expression for this as [^_G]^[A-Za-z0-9_]+ in|ins [-9 -9]..[-9-9] [/[-9-9]..[-9-9]]+
I need a regular expression in java for phone number which that does not allow any character special character only numbers should be allowed.. My sample program is
import java.util.regex.Matcher; import java.util.regex.Pattern; public class c { public String removeOrReplacePhoneNumber(String input) { if (null == input) return input;
1) I don't know what regular expression can i use. 2) I want a line to check that preceding line should have //StorageVersion . 3) n then i will check any string between := K[' and '];. From above log file "'706146.0.22106932'" is the value that i am looking for.
I have to read a text looking for value related to certain variable. The variable are always DE plus identifier from 1 to 99 or DE plus identifier from 1 to 99 and SF plus identifier from 1 to 99. The value can be alphanumeric. How can I get these values? As a start point, I try to use split("DE") but I can get something that is wrong if there is "DE" inside the text that doesn't me interest. I look for scanner but it doesn't work. I guess that there is some way, maybe using regex but I am completely lost ( I have never used regedix before and I am in rush to fix this).
Basically, the text is similar to the below where DE means data element and sf sub field. Some data elements have sub fields while others don't. I guess that there is a way to split with something like DE+anyNumberFrom1To99 = theValueAimed in some array and DE+anyNumberFrom1To99+,+SF+anyNumberFrom1To99 = theValueAimed in other array.
DE 2, SF 1 = 00 SOME TEXT THAT DOESN'T INTEREST ME DE 22, SF 1 = 0 SOME TEXT THAT DOESN'T INTEREST ME DE 22, SF 4 = 1 SOME TEXT THAT DOESN'T INTEREST ME DE 22, SF 5 = 0 SOME TEXT THAT DOESN'T INTEREST ME DE 22, SF 6 = 11 SOME TEXT THAT DOESN'T INTEREST ME DE 22, SF 7 = 90x SOME TEXT THAT DOESN'T INTEREST ME DE 22, SF 7 = 12ab SOME TEXT THAT DOESN'T INTEREST ME DE 99 = 1234 SOME TEXT THAT DOESN'T INTEREST ME
I need to parse an html web page to extract specific information from the tags in Java. For example,
<b>Species </b> Strain </td>
I need to look for the Strain info (Strain is variable in length) in the page. The whole web page is stored as a huge string. I need a regular expression that can identify all the Species and retrieve their corresponding strain info. how to do this or can propose some clever string manipulation methods in Java.
Regular expression which I want to use to split a string. The string could look similar to this:
"a = "Hello World" b = "Some other String" c = "test""
The String is read from a file where the file contents would be:
a = "Hello World" b = "Some other String" c = "test"
After splitting I would like to get the following array:
String[] splitString = new String[] {"a", "=", ""Hello World"", "b", "=", ""Some other String"", "c", "=", ""test""}
I know I could just write a simple text parser to go over the string character by character, but I would rather not do it to keep my code clean and simple. No need to reinvent the wheel.
However, I just cant seem to be able to find the right regular expression for this task. I know that a RE must exist because this can be solved by a finite automaton.
I am trying to implement an example (Book* : Java SE 7 ..By S G Ganesh) for validating an IP address but it fails to validate a valid IP addresses. I found another example on the internet(**) and it works super fine, no problem at all. I edited the code (the one I got from internet) into the exact format like book and it still works super but i don't understand why the books' example doesn't work though both look exactly the same now ,further more, how can i compare String x and y for equality?
public class TestClass { void validateIP(String ipStr) { String one = "((25[0-5]|2[0-4]d|[01]?dd?)(.)){3}(25[0-5]|2[0-4]d|[01]?dd?)"; //copied from internet and edited String two = "((25[0–5]|2[0–4]d|[01]?dd?)(.)){3}(25[0–5]|2[0–4]d|[01]?dd?)"; // copied from book String x = "((25[0-5]|2[0-4]d|[01]?dd?)(.))"; String y ="((25[0–5]|2[0–4]d|[01]?dd?)(.))";
My code is giving me an error at the main method and it says that modifier 'static' is not allowed in constant variable declarations. every program that i searched for had the same code line but none had the problem i do.
I want to do a simple search and replace regular expression of lines. I am very unfamilar with Java regular expressions, and I'm not sure how to do something as simple as what I want to do. I have lines that look like this...
The reason I want to use regular expressions is because I want to use the replaceAll method of the java.lang.String object. If I use replace I have to convert my strings into char arrays, and my code becomes bulky.
