Java Recursion Method Is Not Working - Summing Elements In Array
Feb 2, 2015
I am trying to sum up the elements of an array. When I test my code the sum is always off by one. For example if I input: 20, 40,30 it gives me 89 instead of 90.
This is what I have so far:
public static void main(String[args]){
int size = kbd.nextInt();
int [] myArray = new int [size]
//user inputs the elements of array
[Code]....
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May 5, 2015
***** start code ***
public class AddArray {
public static void main(String[] args) {
int sum = 0;
sum = addArray(myarray);
System.out.println(" hello");
System.out.println("This program will create an array then pass the array to an method to be totaled");
int myarray[] = new int [6];
[Code] ....
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Jan 28, 2015
i have to write a method, The method receives a parameter of two-dimensional array of integers. The method returns the number of the column which has the lowest sum of the integers.I'm allowed to use only recursion! no loops allowed!-of course i need to make a private method that will sum a column as a single array and then i have to do another private method that compares the column , but it doesn't really work .
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Mar 9, 2015
so i have this question where it wants me to create a recursion method that takes ONLY THE ARRAY as a parameter, and without using loops or static variables inside the method, and then the method returns the smallest value in that array. However, i tried making the simple if statements where i compare the first element of the array with the second element using the length of the array and decreasing it to get the next elements and compare it again by calling the recursion method, but the problem is when i call the method again, the length does not decrease, even if i store it in a variable, the variable will initialize itself again, and the length wont change.
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Apr 24, 2015
public static void displayOutputs (int[][] anArray) {
System.out.println("Here is your 2Dim array:");
for (int i = 0; i < anArray.length; i++) {
System.out.println(Arrays.deepToString(anArray));
}
}
This is my code and I get this as a result when I input 10,20,30,...,90 into array[0][0], array[0][1], ..., array[2][2] (3rows, 3columns array)
[[10, 20, 30], [40, 50, 60], [70, 80, 90]]
[[10, 20, 30], [40, 50, 60], [70, 80, 90]]
[[10, 20, 30], [40, 50, 60], [70, 80, 90]]
While I expect to get only
[10, 20, 30]
[40, 50, 60]
[70, 80, 90]
I get no errors at least when I have the same # of rows and # of columns. However, when I have more columns than rows, a compiler stops running when it runs columnSum method.Here's an error message.
Exception in thread "main" java.lang.ArrayIndexOutOfBoundsException: 2
at lab10.Array2DMethods.columnSum(Arrays2DDemo.java:70)
at lab10.Arrays2DDemo.main(Arrays2DDemo.java:111)
Java Result: 1
And here's my code
public static void columnSum (int[][] anArray) {
int sum =0;
for (int col=0; col < anArray.length; col++) {
sum=0;
for (int r = 0; r < anArray[col].length; r++ ){
sum += anArray[r][col];
}
System.out.println("Sum of column " + col + " = " + sum);
}
}
why my code doesn't work when I have more columns.
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Feb 5, 2015
import java.util.ArrayList;
import java.util.Arrays;
import java.util.List;
public class array
{
public static void main(String[] args)
[Code] ...
Is there a way to write this, where, alpha is one array.
Write a program that declares an array "alpha" of 50 elements of type "double". Initialize the array so that the first 25 elements are equal to the square of the index variable and the last 25 elements are equal to three times the index variable. Output the array so that 10 elements per line are printed.
If I have an array of 50 integers, can I break that to read in lines of 10?
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Mar 23, 2015
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public class PA2Delegate {
private long[] start;
private long[] end;
private Long reversal;
private Long sum = (long)(int)0;
[Code] .....
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Oct 15, 2014
I have tried to print array elements using standard print statement. I am getting errors. How to print them. Here is my code:
class arrayEx1{
public static void main(String args[]) {
int a[]=new int[3]; //Declaring Single Diomentional Array
a[0]=10;
a[1]=20;
a[2]=30;
int total=a[0]+a[1]+a[2];
System.out.println("Values stored in a[0],a[1],a[2]elements are :" + a[0] a[1] a[2]);
System.out.println("Total values of a[0],a[1],a[2]elements is :"+ total);
}
}
if i give comma (,) in between above print stament (print statement 1) stil i am getting errors.
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Apr 30, 2014
remove duplicate elements in array using with java
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Feb 5, 2014
I have a project I am currently working on using Primefaces and MySQL. I have a page that will display information queried from the database. I have textfields that will display the data from a given record. But I want to ensure that the displayed data cannot be altered. I decided on disabling the textfields unless the create or edit button were clicked. At which point all textfields will be enabled for editing, and cleared if create button was clicked. I want to push the disabling/enabling of the elements back to a managed bean, but I want to have the bean take in two lists or arrays, one containing all elements by ID and one containing a list of exempt elements. Is there a way I can create a List or Array of the ID's that I can send to the bean? I know little in Javascript and previous attempts to implement it have met with little success.
A short example of the code:
<p:tabView>
<p:tab id=pmDBTab title="PM Database Tab">
<p:panelGrid id="projectInfo">
<p:row id="rowOne">
<p:column id="r1c1" colspan="2">
<p:outputLabel id="searchLabel" for="searchField" value="Search: " style="font-weight: bolder"/>
[Code] ....
I want to create a list that would contain all and another that would contain the exemptions such as searchField, searchCriteria, searchButton, projectList and viewButton. The actual exemption list is far smaller than the list of all children. I have found sources that can disable the elements with a java bean, but I have not been able to find one that would allow me to define those that should and should not be disabled, then vice versa for enabling.
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Jan 12, 2015
I am trying to make a 2d array that keeps track of comparison counts. what I have so far works ok but writes over the previous elements with 0. can't seem to find where I am re-initializing the previous elements.
//this is one of my fill sort arrays
public void fillSelectionArray(int index, long countSum) {
//rand = new Random( );
//for ( int i = 0; i < listsize; i++) {
selectionList[ index -1] = countSum;
// }
[Code] ....
I know I am missing something just not sure what.
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Nov 11, 2014
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Nov 6, 2014
We are supposed to create a MergeSort method without the using recursion. Most of the code is already completed, the only thing that I believe I need are two for loops (an inner and an outter) that will make calls to the merge method. I need implementing the sort method of the merge sort algorithm without recursion, where the length of the array is a power of 2. Keep merging adjacent regions whose size is a power of 2. For ex: lengths will be 1, 2, 4, 8, 16,.
public class MergeSorter {
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//for(int i = 1; i <= a.length; i++) the parameters for the for loop are wrong.
{
merge(0,0,1,a);
merge(1,1,2,a);
merge(2,2,3,a);
[Code]...
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Jan 11, 2015
i'm trying to exit the recursion of a void method but some funny things are happening before and after the return statement.
public static void main(String args[])
{
//code
rec(x,y);
System.out.println("HEllooooooo");}
public static void rec(int x,int y)
{
try
{
System.out.println(x+" "+y+" "+check);
if(x==fx && y==fy)
[code]....
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Mar 25, 2015
How to add the sum of an array with a recursion, but I don't understand how to use recursion. I just understand that it calls back the method. I am nearly done with the code.
import java.util.Scanner;
class Question1{
public static void main(String[]args){
Scanner s = new Scanner(System.in);
int size, sum;
System.out.println("Please input how many numbers will be used");
size=s.nextInt();
[Code] .....
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Feb 26, 2014
I have this method
Java Code:
public static int[] oddNums(int n){
} mh_sh_highlight_all('java');
When a number is passed in, this method returns an array of odd numbers the amount of the number passed in.
So
Ex: Class.oddNums(5) would return [ 1, 3, 5, 7, 9 ]
Class.oddNums(2) would return [ 1, 3]
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Nov 1, 2014
I am practicing some basic recursion and I was trying to solve this problem
Write a method sumTo that accepts an integer parameter n and returns the sum of the first n reciprocals. In other words:
sumTo(n) returns: 1 + 1/2 + 1/3 + 1/4 + ... + 1/n
For example, the call of sumTo(2) should return 1.5. The method should return 0.0 if passed the value 0 and should throw an IllegalArgumentException if passed a value less than 0.
This is my attempt to do it , however my output is always a 0.0 , and i do not understand why :
public static double sumTo(int n ){
if(n<0){
throw new IllegalArgumentException();
}
else if (n==0){
return 0.0;
[Code] .....
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Mar 24, 2015
I am taking the Class Algorithms and Datastructures and got an assignment for Lab that really throws me off. The goal is to create an Array out of a given CSV file, implement several Methods that get the size of array, etc.
I am still stuck in the first part where the CSV has to be imported into the Array. My problem is that I need a mechanism that figures out the needed size for the Array, creates the array, and only then transfers the data from the CSV.
The list consists of the following wifi related values:
MAC-Adress, SSID, Timestamp, Signalstrength.
These are on the list, separated by comma. The Columns are each of these, and the rows are the four types of values making up the information on a certain wifi network.
The catch is, we are not allowed to use any of the following:
java.util.ArrayList
java.util.Arrays
and any class out of java.util.Collection.
So far I used the BufferedReader to read in the file and tried to implement the array, but I get an arrayindexoutofboundsexception.
Below is my Code (Its still an active construction zone):
public class WhatsThere {
public WhatsThere(String wifiscan) throws IOException {
}
public static void main(String[] args) throws IOException {
// WhatsThere Liste = new WhatsThere(String wifiscan);
String[][] arrayListe = new String[0][0];
[Code] ....
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Feb 2, 2015
I am trying to sum up the elements of an array. When I test my code the sum is always off by one. For example if I input: 20, 40,30 it gives me 89 instead of 90.
This is what I have so far:
public static void main(String[args]){
int size = kbd.nextInt();
int [] myArray = new int [size]
//user inputs the elements of array
for(int i =0; i<myArray.length; i++){
myArray[i]= kbd.nextInt();
}
int total = sumNum(myArray,0, myArray.length-1)
System.out.println("The sum is"+ total);
}
[code]....
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Jan 22, 2015
When I insert: title, category, year, artist in 4 Strings And when I press "enter" i put those 4 in a array "large", and then when I can start a new music insert with 4 new string elements and add those in the large array..So: I have an array "large" with the length 19 (or so..)(max ~100 or so)Then I what to: get,in a new array "title",the elements:0,4,8,12,16 (from the large array) and put them in a scrollable list. And when I select one element in the title array I then whant to get 3 remaining elements from this. And put it in a array called selection.
So the "large" and the "title" arrays must be dynamically sizes... or be copied to a larger sized..
1 can it be done with arrays?
2 how do dynamically change the size of for example the array "title"?
3 how do I receive the elements 0,4,8,12,16 and so on, (to (
large.length-3) and add it to the title array?
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Feb 24, 2015
how to read and understand the API's. I've got an array list and I was wondering if there was a method that can randomly re arrange the elements in terms of their index positions.
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Jul 16, 2014
The program I'm working on is supposed to read input from a file and using recursion, print the pattern of asterisks for each value until the value is either < 0 or > 25. For example, if the value was 4, the pattern would look like this
*
* *
* * *
* * * *
* * *
* *
*
The values are stored in a file entitled prog3.dat which looks like this
4
3
15
26
0
I've never used recursion before and haven't been able to find anything showing how it would work with this particular type of problem. Here is what I've been able to come up with so far, but I'm having problems still which I will show following the code.
import java.util.Scanner;
import java.io.*;
public class Program3 {
public static void main(String[] args) throws Exception {
int num = 0;
java.io.File file = new java.io.File("../instr/prog3.dat");
Scanner fin = new Scanner(file);
[Code] ....
Output:
Please enter an integer
*
* *
* * *
* * * *
Please enter an integer
*
* *
* * *
Please enter an integer
*
* *
* * *
* * * *
* * * * *
* * * * * *
* * * * * * *
* * * * * * * *
* * * * * * * * *
* * * * * * * * * *
* * * * * * * * * * *
* * * * * * * * * * * *
* * * * * * * * * * * * *
* * * * * * * * * * * * * *
* * * * * * * * * * * * * * *
Please enter an integer
Please enter an integer
As you can see, I don't know how to make it print the pattern like in the example and am honestly not even sure if this is recursion since I've never actually worked with recursion before.
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May 4, 2015
What is the sum of the array ar elements after executing the following code?
int[] ar = {1,2,3,4,5};
for (int i=0; i<ar.length-1; i++)
if (i%2==0) ar[i]=i;
My professor says the answer is 12 i dont know how he got that answer
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May 17, 2014
I cant get this code to work if wont find the right min and range and its printing out my max three times . This is what I got
public static void main(String[] args)
{
double [] Rainfall = new double[12];
Rainfall[0] = 77.4;
Rainfall[1] = 56;
Rainfall[2] = 61.8;
Rainfall[3] = 62.1;
Rainfall[4] = 57.1;
[Code] ....
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Apr 26, 2015
I was asked to create a word pyramid program using recursion. I understand the concept of recursion (i.e. a method calling itself with the problem it is solving getting simpler and simpler each time) but I am having issues writing the program. Here is my code:
public static void main(String[] args) {
//This program will create a word pyramid by using a recursive algorithm.
//For example, the output of "DOGGY" should be:
//DOGGY
//OGG
//G
//This program will also use a recursive algorithm to accomplish this.
String userWord = JOptionPane.showInputDialog(null, "Hello and welcome to the Word Pyramid program."
[Code] .....
So, if I input HORSE the output should be:
HORSE
ORS
R
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