Recursive Method Called RangeSum
Oct 3, 2014
I'm trying to understand the concept behind this recursive method called rangeSum. This method sums a range of array elements with recursion. I tried summing the elements of 2 through 5, and I tried writing down what actually happens when java executes the program, but what I get when I try to figure it out by paper is different from what netbeans gives me. Here is a snapshot of my scratch work as well as my source code. Netbeans gives me "The sum of elements 2 through 5 is 18" when I try running it but it I get 12 when I do the recursion on paper. I know that the source code is correct because it's out of the book but what am I doing wrong when I try figuring it out by hand?
XML Code:
package recursivecall;
import java.util.Scanner;
/**
* Author: <<Conrado Sanchez>> Date: Task:
*/
public class RecursiveCall {
public static void main(String[] args) {
[code]....
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Apr 29, 2014
Consider the following recursive method that calculates the greatest common divisor using Euclidean method.
PHP Code:
public static int GCD ( int x , int y )
{
if ( y == 0 )
return x;
else if ( x >= y && y > 0)
return GCD ( y , x % y );
else return GCD ( y , x );
}
Trace the above method for x=32 and y=46
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May 9, 2015
As one of the methods of my IntTree tree I have to implement a method that multiplies the level number with the sum of the nodes on the current level. So far I have this, and it doesn't work. What I am wondering is am I on the right track at all with the second return statement?
public int depthSum(){
return depthSum(overallRoot);
}
private int depthSum(IntTreeNode root) {
if(root==null)
return 0;
int level = 0;
[code]....
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May 3, 2014
I have this code and i want to trace it
public static int GCD ( int x , int y ) {
if ( y == 0 )
return x;
else if ( x >= y && y > 0)
return GCD ( y , x % y );
else return GCD ( y , x );
}
(it is a recursive method that calculates the greatest common divisor using Euclidean method )
while x = 32 and y = 46
I want here to understand how the code work ? Precisely , composition and decomposition operations.
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Nov 13, 2014
I was told to write a method that adds up the sequence of the formula (n/2n+1) eg. 1/3 + 2/5 + 3/7 etc. simple enough i suppose. my method is below
public static double Series(int n){
if (n==0)return 0;
else return (n/(n*2+1)) + Series(n - 1);
}
However for some reason or another it returns 0 for any number that is put in. I've written it dozens of different ways with no change and i feel like something fairly obvious is being missed on my part. I am honestly intrigued and interested as to why this is happening. i assume it has something to do with the way i put the actual formula in cause if i put anything else in like simply n the recursion would work as expected.
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Nov 23, 2014
KtMok1t.jpg
Below is what I go so far, but how to do star C and E.
public class PrintTriangle
{
public static void printStars (int star)
{
for (int number = 0; number < star;number ++)
{
System.out.print("*");
[Code] ....
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Oct 22, 2014
Write down a recursive method to remove vowels in string ....
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Oct 21, 2014
How would I modify this version of a selection sort into a recursive method?
public static void selectionSortRecursive(Comparable [] list, int n)
{
int min;
Comparable temp;
for(int index =0; index < n-1; index++){
min = index;
[code]....
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May 9, 2014
a)Write a method that recursively displays any given character the specified number of times on one line.For example, the call: displayRowOf Characters(,5);
Produce a line: *****Write another method that uses a for-loop to perform the same process.
B is something like this ?
for (i=1; i<=n; i++)
i= '*' * n;
System.out.print(i);
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Mar 24, 2014
I have 3 Xml documents that look like this:
model1:
Java Code: <?xml version="1.0" encoding="UTF-8"?>
<model>
<id>1</id>
<nodes>
<id>2</id>
<stencil>TASK</stencil>
</nodes>
<nodes>
<id>3</id>
<stencil>MODEL</stencil>
[Code] ....
After unmarshalling/marshalling in the main class I have created this 3 methods:
Java Code:
public List<Task> extractTasks(Model model) {
List<Task> tasks = new ArrayList<Task>();
for (ModelNodes modelNodes : model.getNodes()) {
if (modelNodes.getStencil().equals("TASK")) {
tasks.add(new Task(modelNodes.getId()));
[Code] ....
When the recursive call to the extractSubModels method is made, I get a **java.lang.StackOverFlowError** ...
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Jan 29, 2015
While studying polymorphism , i have some doubts that i am unable to clarify ..... Here they are :
Suppose our inheritance ladder be :
C1 <- C2 <- C3 <-....... <- C100
where C1 is most general (superclass) and C100 is most specific class .
Now , if i write java code in my main() :
C21 Obj = new C100();
Obj.someMethod();
So, what will happen in scenarios as given below :
Scenario - 1) If someMethod() is only defined in C1 ? How will compiler search for this someMethod() ?Will it be executed ?
Scenario - 2) If that someMethod() is static and only defined in C1 , then how will it be searched and executed ?
Scenario - 3) If someMethod() is only present in C100 , then what will happen ?
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Jun 25, 2014
I want to call getter method from method based on parameter send to this method e.g
Java Code:
void myCrazyMethod(MyDto dto, String prop){
System.out.println("Value of " + prop + ": " + dto.get{Prop}()");
} mh_sh_highlight_all('java');
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Nov 24, 2014
So, I have a gameOver() method that should when oval goes out of bounds abort game but, as soon as I start the game it runs the gameOver method. I've been looking over it for a while trying different things. I think what stood out to me is removing the abort sequence the game runs mostly as it should after, popup is closed and that if I replace game.gameOver(); with ya = -1 the ball bounces off the wall.
gameOver()
public void gameOver(){
JOptionPane.showMessageDialog(this, "Game Over", "Game Over", JOptionPane.YES_NO_OPTION);
System.exit(ABORT);
[Code] ....
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Oct 23, 2014
have written a new class that contains a thread.
From within that thread I try to call a method from within the same class the contain the thread. This method is not being called. I have confirmed that that section of code is being executed in the thread.
If you look at the following code, the thread being run is called MainThread ln 114, and the method it calls that is not being executed is called onprogressTime() ln 105;
package com.example.scott.coloursquares;
import android.content.Context;
import android.graphics.BitmapFactory;
[Code]....
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May 1, 2014
i am trying to write a coin program:Write a class called Coin which will be used by a program called CountFlips.
1. The class, is an object created from this program. It is composed of data values and methods. It should contain a main method and should output the number of flips done (an integer that will be read from the user), the number of heads and tails that occur.
2. The CountFlip class will flip a coin multiple times and counts the number of ‘heads’ and ‘tails’ that result. This class should have a method called flip() of type void; a method called isHead() of type Boolean and a toString() method that will return the current face of the coin as a string.
So i created 2 classes, one called Coin.java & the other CountFlips.java,
PHP Code: package test;
public class Coin {
private final int heads = 0;
private final int tails = 1;
private int facetype;
private int flips;
[code]....
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May 29, 2014
Write an instance method, contains, that has one explicit parameter of type Rectangle. The method should return true if every point of the rectangle determined by the explicit parameter is on or within the rectangle determined by the implicit parameter. It should return false otherwise.
This is what i did so far?
public boolean contains(Rectangle other) {
Rectangle intersect = Rectangle.intersection(this, other);
if ((intersect.left == this.left) && (intersect.bottom == this.bottom) && (intersect.width == this.width)
&& (intersect.height == this.height)) {
return true;
} else {
return false;
}
}
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Apr 22, 2014
i have to "Write a method called addToOverThirty which takes the array nums3 as a parameter. It adds 1 to all numbers that have a value greater than 30 in the array.
Add a call to the addToOverThirty method, then display a message telling what the output is followed by the results For example:The nums3 array after adding 1 to all numbers greater than 30 is10 6 15 and so on (check with the values you assigned to nums3)"its pointless because we were told not to make the array have a number over 30.
import java.lang.*;
import java.util.*;
public class LastProject
public static void main(String[] args) {
int nums1[] = new int[15];
int nums2[] = new int[15];
int nums3[] = {5,2,15,8,26,22,1,29,4,23,30,11,19,6,24};
[code]....
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Jan 8, 2009
Create a method called mirrorImage, which takes two integer arrays as input parameters. You may assume that the two actual parameters have the same length. Your method should return true if the arrays are the reverse of each other. Otherwise mirrorImage should return false.
Examples:
data1:{1,2,3}
data2:{3,2,1}
==> true
[code].....
I'm pointing a place outside of the array or something
runtime error (line 8, column 0): java.lang.ArrayIndexOutOfBoundsException: 10
-> array.ArrayQuestions.mirrorImage()
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Jul 27, 2014
I'm working on a banking program that is supposed to use 3 classes (Account-base class, CheckingAccount, and SavingsAccount) and several methods to display the banking information (ID, balance after a withdrawal and deposit, and the annual interest rate). This should be a pretty simple program, but I'm getting hung up on one portion of it. I'm getting some compiler errors, all of which deal with non-static variables being called from a static context (I'll also post these errors following the code). Up until the middle of last week, we just declared everything as static, but that's changed and I'm having trouble figuring out when to and when not to use static when declaring my methods, hence the compiler errors.
import java.util.Date;
public class Account {
private int id = 0;
private double balance = 0;
private double annualInterestRate = 0;
private Date dateCreated = new Date();
[Code] ....
Here are the compiler errors I am receiving:
Compilation completed. The following files were not compiled:
6 errors found:
File: C:UsersHiTechRedneckDesktopSummer II 2014Computer Programming PrincipleProgram 5CheckingAccount.java [line: 7]
Error: non-static method getId() cannot be referenced from a static context
[Code] .....
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Apr 6, 2014
I'm trying to implement a non-recursive version of the insertion method, but I'm having a bit of trouble. From what I can tell, it's only returning the last two node..
public void insert(Key key, Value val) {
root = insert(key, val, root);
} private Node insert(Key key, Value val, Node x) {
if(x == null) {
x = new Node(key, val, 1);
[code].....
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Oct 21, 2014
How would I modify this version of a selection sort into a recursive method?
public static void selectionSortRecursive(Comparable [] list, int n)
{
int min;
Comparable temp;
[code]....
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Apr 8, 2015
I have a requirement where I have a class as Page which itself contains ArrayList<Page>.Here ArrayList<Page> is nothing but the pages which are accessible from the base Page.I know the depth level ( reading from file) which means how many level I need to go to identify more pages.BUT the problem is how to set the base Page class. I need to set the base Page class but for that I need the objects for the subsequent pages and hence an iterative type of implementation.
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May 17, 2014
I am not sure how to add all the possibilities of elements in an array and find the greatest sum. I want to do this recursively. I don't need any code. How I would do it.
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Apr 20, 2015
I recently wrote a simple recursive program that chooses K objects out of N (I was asked to use the variables N choose the R, however) total objects. Here is the code:
int n = 0;
int r = 0;
//the total number of objects defaults to 0
String nChoice = JOptionPane.showInputDialog(null, "How many objects are there to choose from?");
String rChoice = JOptionPane.showInputDialog(null, "How many object are to be chosen from this group?");
try {
n = Integer.parseInt(nChoice);
[Code] ....
It works fine, however in my class we were given two different formula to implement into our code. I used the one above, obviously. However, the second formula we were given was:
C(n,R) = n!
-------(R!(n-R)!)
I had to get the spacing right.
How do I read this formula? How could it be implemented? What are the benefits (if there are any) from using one method over the other? Which method of calculating N choose K (or, in my case, N choose R) would be more widely accepted?
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Jul 8, 2014
I wrote this tail recursive function that mirrors the iterative version, except that the loop in the iterative version is replaced by an if statement here and then a recursive call. Is this truly recursive? I have seen the fibo(n-1) + fibo(n - 2) version, but is this also an acceptable recursive solution? Why is it never solved this way?
public class FiboRecursive {
public static int fibo (int n) {
int sum = 0;
int n1 = 1;
int n2 = 1;
if (n == 1 || n == 2) {
sum = 1;
[Code] ...
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Oct 26, 2014
I have a given arithmetic expression, which form is (A+B) or (A-B), were A and B are either numbers from 0-9, or another ARITHMETIC Expression.
The first thing that comes to my mind is a recursive function, but how to start...
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