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
[Code] ....
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");
[Code] ....
(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 am supposed to be doing a class assignment that calculates the area of a triangle and outputs with JOptionPane. I was able to fix some errors, but it's uncovering more errors.Here is my code:
import javax.swing.JOptionPane;
import java.util.*;
import java.text.DecimalFormat;
import java.util.StringTokenizer;
public class Area {
public static void main (String [] args) {
double a, b, c; //Input sides of triangle
double x; //Perimeter of triangle
double area; //Area of triangle
StringTokenizer st;
[code]....
Here is the code that I wrote out:
//program that calculates the circumference and area of a circle
import java.util.Scanner;
public class circle{
public static void main(String[] args){
Scanner input= new Scanner( System.in);
double r; //declares radius
[Code] .....
And here is what is displayed in the command prompt when I compile my code:
circle.java:17: error: cannot find symbol
r.input.nextdouble();//entered the radius
symbol: method nextdouble()
location: variable input of type Scanner
1 error
What am I doing wrong?
How to find coordinates of transparent area in the image. I working on .png image which has transparent background and transparent area in the middle of the image. The transparent area in the middle look a like ellipse, so i want to find coordinate of top, bottom, left, and right of that area. I am using opencv.
I have tried to find pixels and from result that i got, i understand that pixel with rgb that equal to 255.0 255.0 255.0 is transparent. what i have in my mind is, if rgb with value that equal to 255 255 255 detected, i will put 1 into arraylist named transparent, and if it not equal to 255 255 255 i will put 0 into the list. So when i look into the list, if there is 1 0 or 0 1 it means that border between transparent area and colored area or vice versa. But, how to know if that border is between transparent area in the middle of image and the image, and not between background and the image. Am i doing this correctly?
Here snippet of code.
Mat imgMask = Highgui.imread(imgfile);
double[] pixels = new double[3];
System.out.println("channel " + imgMask);
for(int x = 0; x < imgMask.cols(); x++) {
for(int y = 0; y < imgMask.rows(); y++) {
pixels = imgMask.get(y, x);
[Code] .....
I have a popup that displays textual info and sometimes gets text input from the user. I'm using the following code:
JTextArea textArea = new JTextArea( getGameHistory( true, -2 ) );
JScrollPane scrollPane = new JScrollPane(textArea);
textArea.setLineWrap(true);
textArea.setWrapStyleWord(true);
textArea.setFont(new Font("courier", Font.PLAIN, 12));
scrollPane.setPreferredSize( new Dimension( 30, 100 ) );
String input = JOptionPane.showInputDialog(null, scrollPane, "Fun Chess ",
JOptionPane.YES_NO_OPTION);
This shows a nice text area and an input field underneath it.The getGameHistory() method just returns a long string detailing the current game.Is there a way of just showing the text area without the input field underneath?Can the text area also be used for input instead?
I've been having trouble with this code for about a week and I've finally got it down to one error. Here is the code:
import java.util.Scanner;
public class Triangle {
public static void main (String[] args) {
Scanner Console = new Scanner(System.in);
System.out.print("Please enter the three lengths of your Triangle: ");
double a = console.nextDouble();
[Code] ....
And here is the error:
Triangle.java:30: error: class, interface, or enum expected
} // End class
^
1 error
how to put the output the the text area this is the code .
/*
* To change this license header, choose License Headers in Project Properties.
* To change this template file, choose Tools | Templates
* and open the template in the editor.
*/
package interns;
/**
*
* @author JosephP
*/
import javax.swing.*;
import java.awt.event.*;
import java.awt.*;
[Code]...
I'm starting with my version of very basic program: calculating area of circle. And of course it doesn't get well. My question: what is wrong in this code?
public class circleAre{
double radious;
void putData(double radi){
radi = radious;
[Code] .....
trying to tranfer content of a text area on one jframe to a text area in another
View Replies View Relatedimport java.lang.Math;
public class triangle {
double area; double s;
public double findArea(double sideA, double sideB, double sideC);
{
s= 0.5 *(sideA + sideB + sideC);
area = Math.sqrt(s*(s-sideA)*(s-sideB)*(s-sideC));
[Code] ...
Errors I am getting:
Triangle.java:23: error: class, interface, or enum expected
import java.util.Scanner
^
Triangle.java:25: error: class, interface, or enum expected
public static void main(String[] args) {
[Code] ....
I've been given a school assignment that reads, "Rewrite the main class Geometry so it takes in the dimensions for the triangle and ellipse as user inputs and create a Triangle and an Ellipse class. Use the appropriate variable types, constants, variable names and computational formulas.
Triangle class will have a computePerimeter and a computeArea methods Ellipse class will have a computeArea method Create Report class
• Create a method createReport that takes the values returned from Triangle and Ellipse and combines them in the following message and displays it. Format the values so that they have 2 decimals.
“The triangle has a perimeter of [perimeter] with an area of [area] while the ellipse has an area of [area]”
• Create a method switchReport that takes the original string from createReport and changes the message to display using the available methods in the String class
“The ellipse has an area of [area] while the triangle has an area of [area] with a perimeter of [perimeter]”"
I've run into a problem when creating the createReport method. Everytime i run it i get incorrect values for the perimeter and area (namely i get zero every time).
my code is as follows:
public class Triangle
{
public double base;
public double height;
public double hypotenuse;
private double tArea;
private double perimeter;
public Triangle()
{
base = 0;
height = 0;
hypotenuse = 0;
[code]....
For the triangle class and
public class Report {
Triangle tri2 = new Triangle();
Ellipse eli2 = new Ellipse();
public Report() {
}
public void createReport() {
System.out.println("The triangle has a perimeter of "+tri2.computePerimeter() +" with an area of " +tri2.computeTArea() +" while the ellipse has an area of " +eli2.computeEArea() );
}
for the report class.the Geometry class allows you to input values and if i skip the report and simply print the perimeter and area they are correct. However with the report class it simply gives me zeros.
Here is the program I wrote for calculating the circumference of a circle.
//circumference.java
//program that calculates the area and circumference of a circle
import java.util.Scanner; //program uses class scanner
public class circumference{
//main method begins execution of Java application
public static void main(String args[]){
[Code] .....
Even though my code compiles and runs without any errors, the program doesn't calculate the circumference.
what I have already tried:
to set the margin of a button - didn´t work
to set anything like padding - didn´t found something for java
to set an empty border - didn´t work
I don´t know what to try next.
My main problem is to enlarge the clickable area without resizing the buttons image.
I am able to draw this image using filloaval() but afterwards when i am calculating some area i have to shade that in the figure in some different color
R is fixed to 100 and d lies between 0 to R
I am trying to custom graphic class..,My task is to replace the specific area color of the image when i select the area & pick the color..,If i choose the hand / body of the T-shirts means the color can change by the user..,
View Replies View RelatedThis assignment requires me to show areas of each shape by using loop. I can do it with abstract and interface , but in this case. I don't know how to use method getArea() to loop for each object
import java.util.ArrayList;
public class TestShape {
ArrayList<Shape> list = new ArrayList<Shape>();
Circle c;
Rectangle r;
Square s;
public TestShape() {
[Code] .....
My homework is to find the surface area and volume of a cone. I have 2 individual java program for the homework and one them already works.
public class Cone {
Cone() {}
double r, h;
double volume() {
return (1.0 / 3.0) * Math.PI * r * r * h;
[Code] ....
The second one I keep getting error mainCone.java:22: error: reached end of file while parsing
public class Conemain {
public static void main(String [] args) {
Cone = new Cone();
Cone.setR(5);
Cone.setH(8);
[Code] ....
I need fixing the second one in order to find the surface area and the volume for cone.
package areatest;
import javax.swing.JOptionPane;
public class AreaTest {
public static double areaTriangle (double length, double width){ //How to calculate the area of a triangle
return .5f * length * width;
[Code] .....
When I try to get the area of a rectangle it gives me 9 no matter what input I give it. When I try to get the area of a triangle it gives me .5 no matter what input I give it. Same with the circle but it always gives me 12.56370...
I have a requirement where in the content of the text area is dynamically populated from the database. I am able to successfully retrieve and display the data on the text area.
However when the content is too large, I am not able to dynamically set the height of the text area. When I try to display the same as a label, the display is flawless, dynamically sets the height as per the content. So, I tried to create a label, with same content and dynamically bind the height to the preferred height as below, but it doesn't work.
// Generate User Note Description
TextArea textArea = new TextArea();
Label text = new Label();
// SETTING THE TEXT TO A LABEL TO RETRIEVE THE HEIGHT
text.setText(usrNotes.getNote().trim());
[Code] ....
How can I read a text file present in my local directory say (C://test.txt) , iterate and populate the values of test.txt into a text area of the JSP page?
Contents in the test.txt file:
username:test
password:test123
domain:test321
DBname:testDB
I have problem with my simple program. I tried put some text in my text area using button1 but textListener in RighButtons is always null and it's give me NullPointerException.
WriteToArea - interface
public interface WriteToArea {
public void add_a(String text);
}
BaseFrame
public class BaseFrame extends JFrame{
[Code] .....
I try to create Java Swing Desktop application which show Road map of some area in JFrame. But pc not connected to internet it will be in LAN. Map should be like if we scroll the mouse we go down from height in map. Like zooming the area.
I try to find out by google i get lots of forum links but each showing me.
1. I have to do web application.
2. Google not support 'without internet' map facility.
3. I should use lots of jpgs which store in folder for showing map from various height so it look like when we see any map in Google Earth application.
I found goworldwind.org but not clear understanding right now.
In my application, some text should be added to a text area in response to a click on a button. So as an action listener to this class, I made another class which implements the ActionListener.
Inside this class, I have obtained the text which I want to be added to the text area. But the text area is in another class and for the action listener I wrote another class.
Now the problem is that when I try to add the text to the text area by the following line of code, it says that textArea_1 can not be resolved or is not a field.
Java Code:
ParentPanel.textArea_1.setText("Name:"+ncrarray[0]+"
Code:"+ncrarray[1]+"
Rank:"+ncrarray[2]); mh_sh_highlight_all('java'); What should I do about it?
Even if I try to write a method like the following in the class in which the text area is created, it gives the same error.
Java Code:
public void printTextArea(String text) {
textArea_1.setText(text);
} mh_sh_highlight_all('java');
The text area is present inside a constructor of the class. I am writing the method outside the constructor (ofcourse).
I have to write a gui program where I can enter a file name and then it gets displayed in a text area when I click Open. Conceptually, I do not get this. I was thinking of appending the text file into a string or something, but I guess I'm confused on how it all works and how I can open the text file. Not asking for the code, but just a compass or something.
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