Java Objects And Classes - System Of Linear Equation
Mar 15, 2015
The question states: Design a class named LinearEquation
for a 2 x 2 system of linear equations:
ax + by = e
cx + dy = f
Where
x =
ed − bf/ad − bc
y =
af − ec/ad − bc
The class contains:
- Private data fields a, b, c, d, e, and f.
- A constructor with the arguments for a, b, c, d, e, and f.
- Six get methods for a, b, c, d, e, and f.
- A method named isSolvable() that returns true if ad−bc is not 0.
- Methods getX() and getY() that return the solution for the equation.
Write a test program that prompts the user to enter a, b, c, d, e, and f and displays the result. If ad − bc is 0, report that "The equation has no solution."
I believe that my program is correct because I am able to compile it and get no errors, however I have no clue how to display the information for x and y or display this equation has no solution if ad-bc=0.
Java Code:
import java.util.Scanner;
public class Exer911 {
public static void main(String[] args){
// Create a scanner system to hold the numbers for each variable
Scanner input = new Scanner(System.in);
// Prompt the user to enter a number for each of the variables
I develop a finite element code at java. I am looking for efficiency solver and fast for large, sparse , symmetric and positive define matrices .
i used in jblas but i encounter in problem when the matrix has high condition number(ill condition number) and i get error for singular matrix while in mathematica i succeed to solve that system without problems...
Any good solver and fast solver package in java can i use for solving that system?
So i was assigned to write a program that would print the answer to the system of two linear equation. the form of ax+by=c and dx+ey=f..I wrote this program, but it is incorrect since I tried it out on my terminal and I keep getting incorrect values.
import java.util.Scanner; public class Quest4 { public static void main(String[] args) { Scanner input = new Scanner(System.in);
I'm currently trying to build a project for a mock checkout system. Basically it has to allow for users to browse through a list of items and add and remove products to the shopping cart as well as keep track of everything, dynamically updating the total price of the items in the checkout. In addition I also have to allow for the use of multiple checkouts. I have the main gui built but just trying to ascertain the best manner in which to build everything behind it.
Any Technique that will decide which one of the fields (Integer, Address, DOB, String, Float) are user defined type. (An outsider class should used that will identify the Java classes and the user-defined classes.)
I'm finding common elements in a collection of arrays. This is my code so far.
import java.util.ArrayList; import java.util.List; public class CommonElements //< T extends Comparable<T> > { Comparable[] comparable; Comparable[] tempArr; Comparable[] tempArr1; Comparable[] newArray = new Comparable[tempArr.length]; int comparisonCount;
[code]....
I'm using this method to sort through my array. The method accepts a collection of arrays (of varying length and of any type) as input, the algorithm input should be no greater than n(k-1). I know I can solve it using a quadratic algorithm, but it won't meet the requirement of the assignment. I did have an idea of storing all my algorithm in one giant array. After storing as one giant array I was going to sort it. After sorting I was going to compare each array side by side and see if they are the same. Here is note my teacher provided.
Note About Testing You will need to develop several sets of test collections for testing your algorithm. The grading rubric mentions covering the case where all the test collections have the same length, as well as covering the case where the test collections are of different lengths. You will also need to think about what constitutes the worst case scenario for this algorithm, since only that scenario will make your analysis of total comparisons performed a meaningful one. You can use the formulas in the grading rubric to tell you how many comparisons you should expect in the quadratic and linear cases. For example, if you have 5 total collections (1 query collection and 4 test collections), each of which contains 10 elements, the total number of comparisons performed in the worst case should be: (k - 1)N2, which for k = 10 and N = 10 is: (5 - 1)102, or 400 comparisons. For the linear algorithm, you should only have N*(k - 1), which is 10*(5 - 1), or 40 comparisons.
Here is Q/A that my teacher provided:
1. Are the elements in the collections already sorted?The input collections may or may not be sorted. Don’t assume that they are sorted.
2. Can I sort the elements in the collections? Am I supposed to sort the elements in thecollections?Yes, you can sort the elements in the collections. It is not required that you do so, however..
3. If I sort the collections, should I count the element comparisons that are performed by the sorting algorithm?No. The only element comparisons you should count are the ones that are directly used to find the common elements. Ignore comparisons performed by any sorting algorithms you use.
4. How do I extract an individual collection from the Object[] collections argument of the findCommonElements method?You will need to typecast each collection as type Comparable[]. For example:Comparable[] currentCollection = (Comparable[])collections[i];
5. Why are we using a one-dimensional Object array instead of a two-dimensional array of type Comparable (e.g., Comparable[][])?In Java, arrays are treated as objects, so only a variable of type Object[] can contain arrays. A variable of type Comparable[] can only contain Comparable elements, not arrays. A variable of type Comparable[][] also can only store Comparable elements. Although it is possible to organize the elements such that all the elements at indexes [1][i], for example, are considered to comprise a collection, this is not the same as having an array that contains other arrays. The additional bookkeeping is required to keep a 2D array organized is more complex than simply performing the typecast described above.
6. Can I use other data structures besides arrays; e.g., HashMaps?No. Although it is easier from a programming perspective to use higher order data structures like HashMaps to find common elements, using these structures simply hides the details. If you were to examine the implementations of those structures, you would probably find that they use relatively inefficient algorithms such as sequential searches to find elements. Additionally, if you use library components, you have no way of counting the number of comparisons performed, since you don’t have access to the source code of those components.
7. Is this a trick question? I can’t think of any way to get below NlogN comparisons.It is not a trick question. It is possible to solve this problem using a number of comparisons proportional to (k – 1) * N.
Allow the user to specify the number of terms (5 terms are shown) to use in the computation. Each time around the loop only one extra term should be added to the estimate for PI.
Alter your solution from part one so that the user is allowed to specify the precision required between 1 and 8 digits (i.e. the number of digits which are correct; e.g. to 5 digits PI is 3.14159), rather than the number of terms. The condition on the loop should be altered so that it continues until the required precision is obtained. Note that you need only submit this second version of the program (assuming you have it working).
My output for part 1 is :
Enter number of wanted terms for value of PI 100 PI = 3.1666666666666665 Number of Term = 2 PI = 3.1333333333333333 Number of Term = 3 PI = 3.145238095238095 Number of Term = 4 PI = 3.1396825396825396 Number of Term = 5 PI = 3.1427128427128426 Number of Term = 6 PI = 3.1408813408813407 Number of Term = 7 PI = 3.142071817071817 Number of Term = 8 PI = 3.1412548236077646 Number of Term = 9 PI = 3.141839618929402 Number of Term = 10 ................ and so on
I know you have to compare value of current Pi to the previous one but I'm stuck.
I'm quite new to Java. I have some trouble with understanding how to get two classes to get objects from each other (if that is the correct term).
Lets say I have a login class, in which I have a method checking what the user has entered into the console (I have not displayed the whole code, but this class works as it should and give the user an option to enter username and password and return it true if entered correct).
public static boolean validateUserPass(String userName, String password) { String[] user = {"admin"}; String[] passwords = {"firkanten"}; boolean check = false; for (int i = 0; i < user.length; i++) { if (userName.equals(user[i])) { if (password.equals(passwords[i])) { check = true;
Now, in another class I want a display box to appear on the screen and give the user three options: Click yes, no or cancel. I get this to run perfectly alone, this is not the hard part for me. I want the display box only to appear when the correct username and password is given, but I can't seem to figure out how to do this probably.
I recently had to work on a very simple banking application. Since customers provide their account numbers when they go to the teller to perform a transaction, I chose account number as the key to uniquely identify a customer. To address the fact that a customer can have multiple accounts, I decided to have an entry for every account the customer had, as part of my Teller class, so that he can identify himself with any of his active account numbers. When I was discussing this design with my friend, he felt it was bad and that I had to have a CustomerID field to uniquely identify a customer. I can't seem to understand why we can't do that with account numbers belonging to the customer?
For class, we need to create a word game using classes and objects.
The game is played in rounds. The player is presented with a word that is missing letters. The player has to fill in the missing spaces with their letter guesses. The words presented are chosen with a random number generator which has been provided for us. At the end of the game, the player is shown their score.
In steps, I have to:
-Welcome the player. -Present the puzzle. -Allow the player to fill in the blanks. -Have the program check responses for correct/incorrect input. -End the game if they have three misses, or continue if they complete the puzzle.
Now, to start, I have a class for the number generator, a class to store the array of 25 words, and a class for the game itself.
I have seen many ways of describing what objects are, one being that objects are a user-defined datatype. However, if objects are datatypes, then what does that make classes? To me, it seems as though classes should be the "types" of data defined by the programmer, and objects should be the specific "values" of that user defined data type. As an example, an integer would be a class, while 1 would be a "value" of that class, i.e. an object. From this point of view, I don't see why a specific number would be a data type... Therefore, why do we say that objects are user defined data types rather than classes?
Design a class named LinearEquation for a 2 X 2 system of linear equations:
ax + by = e cx + dy = f Where x = ed − bf/ad − bc y = af − ec/ad − bc
The class contains:
- Private data fields a, b, c, d, e, and f. - A constructor with the arguments for a, b, c, d, e, and f. - Six get methods for a, b, c, d, e, and f. - A method named isSolvable() that returns true if ad−bc is not 0. - Methods getX() and getY() that return the solution for the equation.
[code].....
how to display the information I need to display. Also I am not so sure that I wrote the code properly, I do not get any errors when I compile it.
I am having some trouble with linear search of a customers last name. I can't seem to get it to work. I have looked up examples but cant find many with Array Lists. Here is my code.
import java.util.ArrayList; import java.util.Scanner; public class AccountDriver { public static void main(String[] args) { ArrayList<Account> al = new ArrayList<Account>(); ArrayList<Customer> cust = new ArrayList<Customer>(); Scanner scan = new Scanner(System.in);
I am attempting to find the element that holds the lowest time ( i have used System.currentMillisTime ) in the array using a linear search and to then print the times held by the array in lowest to highest order . While i understand how to do a linear search using user input as the key i am not to sure how to do it by initializing a search key in the program to the lowest number and have little experience in using a search in a program that is not a simply linear search. i have attempted to code this, as seen below, but i know i am definitely wrong and i have tried another of different ways even Array.sort and then a binary search .
static long store_MAX[]; // Now an ‘array’ of ints static int deptSize; // Holds the length of the buffer private int shopper_MAX; // Holds the number of items in the buffer
Here is my full program, you can find these lines of code on lines 64 and 70.
Java Code:
import java.util.Scanner; public class StockTransaction { public static void main(String[] args) { // TODO Auto-generated method stub //Variable Declaration Section
I'm making a stock system for the heck of it,so everything was going great until I hit the loop I am trying to use a for loop to add stock to the stock system,any way the question is maily about loops.How come I cannot declare a variable outside a loop and assign a value to it,for example I can declare as follows and I will not get an error,
but in my code(and yes its the only error I get I tested it) I get an error and can only declare and assign a value inside the loop,the reason for this is because I wanted to get the value from another class and use it in the loop ok so heres the code from both classes.
public class mainn{
public static void main(String [] args){ stock first = new stock(); int internal; internal = first.wanted;
I just want to calculate search time for my algorithm . How to get system time in java other than System.nanotime() and System.currenttimemillis() as these methods does not returns consistent time for same input is their another option to get system time???
So Ive got to make a turtle on an image draw a semicircle that starts at the top of a circle and goes down and to the left, changing colors halfway through. I've got everything down, I can draw the turtles and make them do straight lines. My problem is more math related. I need to use the equation of a circle, give it points, and figure out how to write that code in java.
We use the equation for a circle: (x - a)^2 + (y - b)^2 = r^2
I want make a math equation game. usually math game use equation for the question and we answer that equation. ex : what is the result of 2*5 / 2+2/ 2^2 etc. and we answering that. but i want to make it different so i want to make the equation answer as the question and the equation as the answer of the game. Ex : the question is 54 so we can answer it with 9*6 or 24+30. and this is my java code
package coba; import java.util.Scanner; public class Coba {
public static void main(String[] args) { double angka = Math.random()*70;
[Code] ....
but when i run it the error code show like this : Quote
I just created a program to calculate the roots for a 2. degree equation, When I first created my program, I defined the r1 and r2 as double, but got an error saying they needed to be defined as String, why is that?When should I be using string? I am new to java and I have mostly only used int, double and Boolean so far.
import java.util.Scanner; import java.text.DecimalFormat; public class c3e1 { public static void main(String[]args){
I have been working on making a Java application for the Game RuneScape. My goal is to make an Application to where you register on the application and it saves the information in a file. I am also looking to make it so you can transfer money from Runescape to your Account on my Application by submitting a ticket. When you submit a ticket you get assisted by one of the moderators, they trade you in the game and take the money, and then they take that money out of their current account. Admins are allowed to give moderators money via their account or another method. My issue is creating the ticket system. I want to be able to do this all via the application. So basically what i have currently for the application is a chat room, with different rooms available to go into by the users. So I need to make the tickets show up only to Moderators and Admins in the general chat room.
1) I'm trying to use a logarithm to determine the length of a user input number. I keep getting an error stating <> indetifier expected. I'm assuming this means that the program is not recognizing the function of a logarithm. I know that normally you can include that information in the method, but my teacher has stated specifically that each of these methods be called something else, as shown in the code.
2) I'm not quite sure I understand how to assign the numbers I obtain from the modular equation to a certain position in the array. As I'm asking the user to input any number these values can change so therefore I can't simply state that first number = this place.Here is my code:
import javax.swing.*; import javax.*; public class getSize { public static void main( String[] args )
I am running into some trouble with Line-Plane intersection, my method works, provided I am perpendicular to the plane I want to intersect. This is caused be the plane equation (with my given x, y, and z coordinates, the equation is -Z - 1 = 0). So the equation is only relying on the Z value of anything inputted. Is there another way to calculate the equation of a plane that would rely on all axis? Here is my current code:
Java Code:
Vector3f A = new Vector3f(0, 0, -1); Vector3f B = new Vector3f(0, 1, -1); Vector3f C = new Vector3f(1, 1, -1);
I search this source code in google about library system then i run this in my JCreator then that error appear . I think that problem is all about "main". where can i put that main ?
