Using Two Dimensional Arrays To Make Calculations
May 10, 2014
I am having problems figuring out how to make calculations using a two dimensional array. The problem is finding the distance of a projectile given the launch velocity and angle. The equation is x = v^2*sin(2theta)/g. I understand how to implement this equation using the toRadians() and Sin() methods. What I don't understand is how to calculate the distance values with a multi dimensional array.
double [][] data = { {20, 15},
{50, 35},
{80, 45},
{100, 65},
{150, 85},
{10, 50},
{110, 8}};
My array has the velocities on the left and angles on the right. I tried using nested loops but I don't know how to access the two pieces of data at a time which I need.
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Jun 28, 2014
I mainly would like to know is a int[4][4] or a int [4*4] is more efficient to use. Which takes more storage? Which requires more to process? that kind of stuff.
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Apr 13, 2014
I am having trouble grasping 2 dimensional arrays .I have a certain problem:
String[][] words = {
{"Red", "Blue", "Green"},
{"Orange", "Purple". "Yellow"}
[code]....
I ran the code and got OrangePurpleYellowRedBlueGreen.
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Jun 18, 2014
I have the program bellow that grades students(based on a two dimensional array with the answers) and i need to make it display the students based on the grades/scores in ascending order . I did that in two ways (using a array and a two dimensional array) but i have a hunch it can be done much more simple then i did it (but still using array object and nothing else ) .
public class GradeExam {
/** Main method */
public static void main(String args[]) {
// Students' answers to the questions
char[][] answers = {
[code]....
My first solution creating an array with the grades for sorting :
public class C8_3 {
public static void main(String args[]) {
// Students' answers to the questions
char[][] answers = {
{'A', 'B', 'A', 'C', 'C', 'D', 'E', 'E', 'A', 'D'},
{'D', 'B', 'A', 'B', 'C', 'A', 'E', 'E', 'A', 'D'},
[code]....
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Dec 8, 2014
I need to write a class that represents and image of RGB pixels. This class uses a two-dimensional array of object type that represents R,G and B values.
When I compile the class it completes successfully. However, when I try running a "tester" class , I'm encountering errors in a few methods. I've been trying it out for 2 days now, but unsuccessfully thus far..Those method are : rotating the image by 90 degrees clockwise (and vice versa , but I just use clockwise method 3 times for that) , shifting the image sideways, and shifting the image up/down..
I've attached the whole source code for the class , and the list of errors I get when I try to run my tester. URL...
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Feb 4, 2015
The international Olympics Committee has asked you to write a program to process the data and determine the medal winners for the pairs figure skating. You will be given the following file: Pairs.txt
Which contains the data for each pair of skaters. The data consists of each skater's name, their country and the score from each of eight judges on the technical aspects and on the performance aspects. A typical record would be as follows:
Smith
Jones
Australia
5.0 4.9 5.1 5.2 5.0 5.1 5.2 4.8
4.3 4.7 4.8 4.9 4.6 4.8 4.9 4.5
The final score for each skater is the sum of the average of the two categories of score. Design a class to hold the above data and the final score. Read the data in from the file and calculate the final score for each pair. Sort the array of objects , and display the results on the screen in order, giving special prominence to the medal winners.
Here is my CLass:
public class Skaters {
private String name1;
private String name2;
private String country;
private double [] arrTech = new double [8];
private double [] arrArt = new double [8];
private double score;
[code]...
how do i print my 2 arrays using the file? i got the name1, name2 and counntry to print but im stuck on printing the scores that are stored in the arrays. Also, i have to print the average for each array. one is for techniques and the other one is artistic. as you can see i already wrote the code for it but im stuck in printing it.
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Dec 6, 2014
I am trying to create a program for class the uses two dimensional arrays. I am stuck on the second step that states Use two parallel arrays. One is a two-dimensional array -- a row of this array will hold six values in this order: [0] number of hours worked, [1] hourly pay rate, [2] gross pay, [3] net pay, [4] federal withholding, and [5] state withholding.
This is what I have so far:
Java Code:
double [][] data = new double [30][6];
String [] names = new String [30];
String str = null;
String detail = null;
int n = input(data, names, inputFile); mh_sh_highlight_all('java');
(there's more but i don't believe it pertains to this question)
My question is how would I create this array. Or, is that right above? I've searched online and in my book and I just don't understand.
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Dec 2, 2014
Recently I have missed a few weeks of my class due to family emergencies. Because of this I have missed very important lectures. My professor has assigned me the following assignment:
Prices Write a Java program that specifies three one-dimensional arrays names price, amount, and total. Each array should be capable of holding 10 elements. Using a loop, input values for the price and amount arrays. The entries in the total array should be the product of the corresponding values in the price and amount arrays. After all the data have been entered, display the following output:
Total Price Amount
==== ==== ======
Under each column heading display the appropriate value.
I know how to display everything using printf, how to create the actual arrays and define the array size, but I am confused on how and what loop to use and how to construct it. This is what I have managed to write up so far:
import java.util.Scanner; // Imports the Scanner class
import java.text.DecimalFormat; // Imports the DecimalFormat class
public class Prices
{
public static void main(String [] args)
{
double[] price = new double[10];
double[] amount = new double[10];
double[] total = new double[10];
// Create a new Scanner object
Scanner keyboard = new Scanner(System.in);
} //End of main method
} // End of public class
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May 9, 2015
Im trying to make a tic tac toe game that you play against the computer using a random number generator and two dimensional arrays for the game board. Im not trying to make a GUI, the assignment is to have the board in the console, which I have done. I have run into a few problems with trying to get the computer player to correctly generate 2 integers and have those two integers be a place on the game board. Here is my code so far.
import java.util.Random;
import java.util.Scanner;
public class TicTacToe {
private static Scanner keyboard = new Scanner(System.in);
private static char[][] board = new char[3][3];
public static int row, col;
[Code] ....
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Nov 15, 2014
I need to do a rectangle using boolean array where true elements are the borders of the rectangle, and false elements are the inner space. I imagine that the first and last rows and columns must give the true element,
public class Functionality {
public static boolean[][] rectangleArray(int n, int m){
boolean[ ][ ] matrix = new boolean[n][m];
for(int i = 0; i <matrix.length; i++){
for(int j = 0; j < matrix[i].length; j++){
[code]....
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Mar 13, 2014
I have a 2x2 matrix and a 2 dimensional array.Let's say, my matrix is [a b] and array is [[1, 2], [3, 4], [5, 6],[23, 11]] .I need to multiply each 1 dimensional array in above array with the matrix.For instance,
[1, 2] multiply with [a b]
[3, 4] multiply with [a b]
[5, 6] multiply with [a b]
[23, 11] multiply with [a b]
So, each 1 dimensional array in there will be multiplied with matrix [a b] (same with matrix multiplication).how to do that multiplication in java. But I confuse how to 'release' each 1 dimensional array from the first array so I can do multiplication.How to do that in java?
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Feb 13, 2015
I am almost done with the assignment, but I am having an issue with this step: "Create a field to hold the gallery commission. This field cannot be set from outside the class. it is computed as 20% of the price, and should be set whenever the price is set. Put the code to calculate and set the commission in the setPrice() method"
import java.util.Scanner;
public class PaintingHarness
{
public static void main(String[] args)
{
// put code here
// Created object so we can take input from the Scanner
Scanner input = new Scanner(System.in);
Painting myPainting = new Painting();
[code]....
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Feb 18, 2015
I've created a method to calculate the ratio of one vowel to another, but I was hoping to get some feedback on another way I could approach the problem. The first bit of code is to find the vowels and assign them to an array ( for me, it seemed the easier thing to do in order to easily access the data). In the other bit of code, I have a method with two arguments (the vowels) to calculate the ratio.
public void findVowels(StringBuilder message, String delimiter) {
subString = message.toString().toLowerCase().split(delimiter);
vowelCounter = new int[5][subString.length];
// Remove all whitespace
for (int index = 0; index < subString.length; index++) {
subString[index] = subString[index].replaceAll("s", "");
[code]....
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Jan 25, 2014
A complex number is defined as z=a+i*b, where a is the real part, and b is the imaginary part. In other words, in order to define a complex number, we need the two floating numbers a and b. Write methods that perform for each of the following operations with complex numbers z1 = a1 + i*b1, and z2 = a2 + i*b2:
Addition: z1 + z2=(a1+a2) + i*(b1+b2)
Subtraction: z1 - z2=(a1-a2) + i*(b1-b2)
Multiplication: z1*z2 = (a1*a2 - b1*b2) + i*(a1*b2 + b1*a2)
Division: z1/z2 = (a1*a2 +b1*b2)/(a2^2 + b2^2) + i*(b1*a2 - a1*b2)/(a2^2 + b2^2)
Create a test program that asks for the real and imaginary parts of two complex numbers from the user, and displays the results of the four operations, writing the formula as shown above, and replacing the a1, a2, b1 and b2 with the numbers entered by the user.The professor used the incorrect complex number equations and has notified the students of his error. I have run into a few problems thus far.
1. I'm not sure how to use floating numbers with the Math.pow(double, double) function, since its requires doubles!? So instead of using floating numbers, I've knowingly switched them all to double in order to see if the code itself is working properly for the purposes of this forum. Is there a way that I can modify this function so that it will work for floating numbers?
2. Regarding the division method, an error stating that c and d have not been initialized and I'm not sure how to change it because the other calculation methods work fine. Why do I need to initialize c and d in the division method and not the others?
3. Am I on the right path? I have surfed the web to see how others completed the program and they all appear very different than mine...
package program5;
import java.util.Scanner;
public class Program5 {
static double a, b, c, d;
static double i = Math.pow(-1,1/2);
[code]...
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Mar 7, 2014
I have made a simple form, it consists of 3 text box's textbox1, textbox2 and textbox3 as well as 1 button button1. What I want to be able to do is put numbers into textbox 1 and 2 and then show the multiplication of these numbers in textbox 3 when the button is pressed and I was wondering what is the standard way of reading these numbers from the text box and allowing us to do the conversion obviously in the textbox its a string and we need to convert to an int or double or whatever to be able to perform calculations on them then convert it back into a string to display in text box 3?
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May 28, 2014
this program works but returns zero for all the calculations. I checked everything there is no error but I dont know why is returning 0.
package mshproject3;
import java.util.StringTokenizer;
import javax.swing.JOptionPane;
public class HayloFactoryController {
public static void main(String[] args) {
String firstName = "";
String lastName = "";
String phoneNumber = "";
int aNbrOfVehicles = 0;
int aNbrOfFuelTanks = 0;
HayloFactory factory;
[code]....
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Mar 26, 2014
It seems that all of my arrays in the class Calculations are out of bounds, and I do not seem to know why.
Java Code:
/**
public class DataAnalyzer
{
public static void main (String[] args) {
//This creates an instance of ReadFiles
ReadFiles aReadFiles = new ReadFiles();
Calculations aCalculations = new Calculations();
[code]....
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Dec 4, 2014
I have some data files that take this form:
D14
J3
N1
a26
[code]...
I also have this code that takes the file, goes through each line using a loop and counts the total of all the integers on each line, it also then loops and takes each integer on each line and divides it by the total calculated in the previous loop but I don't know what code to manipulate the strings to do these calculations. After these calculations I want to write the updated values to the text file I originally took the data in from. So as an example the total I already for this file to be '232' so the first line would be D 0.06 because 14/232 = 0.06034482758 and rounded to 2 decimal points is 0.06.
import java.io.File;
import java.io.FileReader;
import java.io.LineNumberReader;
import java.io.PrintWriter;
import java.util.Scanner;
public class Normalise {
private static Scanner scanner;
//private static PrintWriter out;
[code]....
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Apr 6, 2014
It's an RMI program that has to be able to return the mean, mode and median of a set of numbers.It's composed of 4 classes; a client, an implementation class (with the math), an Interface, and a server class.
import java.rmi.NotBoundException;
import java.rmi.RMISecurityManager;
import java.rmi.RemoteException;
import java.rmi.registry.LocateRegistry;
import java.rmi.registry.Registry;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.List;
import java.util.Scanner;
import java.io.*;
[code]....
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Nov 23, 2014
I am doing a calculator using stacks but when i try to calculate I getting the wrong data example stack contains 8 and user enter -3 stack should change to 5.
package comp10152.lab5;
import java.util.Scanner;
import java.util.Stack;
[Code].....
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Oct 13, 2014
/**
* In this program, use for and while loops with calculations to get the lottery odds.
*/
import java.util.Scanner;
import java.util.Random;
public class Lottery
{
public static void main (String []args)
[Code] .....
I need getting my numbers matching. When, I run the program each time no matter what number it keeps saying sorry no matches. However, I do need the program to have matches.
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Apr 22, 2015
I've created several methods in another class to perform certain matrix calculations. Do I need to have mutator method in this calculation class to define the column length of the matrix object? I understand why the following code is not working, but I was hoping to get a quick and easy workaround. I'm not sure how to initialize the size of the column for newMatrix within the method.
public int [][] sum(int matrixOne[][], int matrixTwo[][]) {
int sumMatrix [][] = new int[matrixOne.length]["WHAT TO PUT HERE"];
for (int i = 0; i < matrixOne.length; i++) {
for (int j = 0; j < matrixOne[i].length; j++) {
sumMatrix[i][j] = matrixOne[i][j] + matrixTwo[i][j];
System.out.println("matrixSum" + sumMatrix[i][j]);
}
}
return sumMatrix;
}
Then I will use this method to print the new matrix:
public void printMatrix(int newMatrix [][]) {
for (int i = 0; i < newMatrix.length; i++) {
for (int j = 0; j < newMatrix[i].length; j++) {
System.out.print(newMatrix[i][j] + " ");
}
System.out.println("");
}
}
Is all of this overkill and should I just define all the methods within the same class to avoid these issues?
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Dec 12, 2014
I have to ask the user to enter 4 whole numbers, and then the program will calculate:
> x numbers are positive and even
> x numbers are positive and odd
> x numbers are negative and even
> x numbers are negative and odd
but I have trouble with the conditions. How do I form the conditions to calculate this? My professor said I can do this with only four IFs (or ELSE IF). This is what I did:
import java.util.Scanner;
public class Calc{
public static void main(String [] args){
Scanner sc = new Scanner(System.in);
int pe = 0, po = 0, ne = 0, no = 0;
/* four variables for each result
pe - positive even
po - positive odd
ne - negative even
no - negative odd
[Code[ ....
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Nov 22, 2014
I am trying to put together a small application in my spare time. Nothing major, but one thing I want it to do is accept a few inputs, and take those and add them to a table with columns for use later (printing, calculations, etc). I was originally looking at something like Jtable, but that looks just like an excel spreadsheet done Java, so not what I'm looking for.
I'm looking for something that's read-only, where I can insert data from input fields, and then perform calculations with the column data later.
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Nov 23, 2014
I have written a simple grade average program. This is my code:
package programs;
import java.util.Scanner;
public class GradeAverage {
public static void main(String[] args) {
Scanner input = new Scanner(System.in);
int number;
int counter = 0;
int grade;
[Code] ....
Now the program is working just fine but what I don't like about it is the fact that you have to enter the number of grades before entering the grades. What I would prefer is to write your grades, hit some button that is reserved for calculating the average and then get the output.
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Sep 12, 2014
Here are the instructions to my assignment:
A shopkeeper in Diagon Alley needs you to write a program that will calculate the correct amount of change due to a customer. (In Diagon Alley they use three coins with different values, given below).
1. Prompt the user to input the amount of sale in Galleons, Sickles, and Knuts.
2. Prompt the user to input the amount of money given by the customer in Galleons, Sickles, and Knuts.
3. Create constants that represent:
a. 1 Galleon = 17 Sickles
b. 1 Sickle = 29 Knuts
4. Perform the necessary calculations and conversions to compute the correct change in the least number of coins.
5. create a formatted receipt recording the entire transaction.
Here are what is steps 1 and 2 and 5 but problem with are 3 and 4. I need to create the constants and use proper conversions to give the right amount of change back.
Java Code:
import java.util.Scanner;
public class OperatorFormatting {
public static void main(String[] args) {
Scanner input = new Scanner(System.in);
System.out.println("Welcome to Flourish and Blotts");
[Code] ....
Basically, on steps 3 and 4 which are creating the constants and using the to make the proper conversions to give the customer the proper amount of change Due.
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