What approach Collections.reverse() uses to reverse list? My task is to implement and compare reverse methods from list and i already did reveres with Recursion, Swap, Reading backward with creating reversed copy.
Does Collections.reverse() use different approach from those i already did?
i tried everything but its giving me errors. i tried the for loop but its giving me something else.
this is what i have to do Write a recursive method that prints out the data elements of a linked list in reverse order.
Your method should take in as a parameter the head reference to a linked list. Then, write a recursive method that returns a count of the number of elements greater than a given threshold. You may assume that the data elements in the linked lists are ints. The parameters of your method are a reference to the linked list and a int value representing the threshold.
public class recursion3
{
public static void main(String [] args) {
char a [] = {'A', 'B','C','D','E'};
System.out.println(a);
}
public static String reverseString(String s) {
if (s.length() <= 1) {
[code]....
I am creating a recursive method to reverse a linked list in java. It works the first time when I call it, but I want it to work where I call it a second time and it reverses it to the original state. How can I get that to work with this implementation?
public void reverseList() {
System.out.printf("%-16s%-3s%n", "Name", "Score");
System.out.println("--------------- -----");
reverseList(first);
} public void reverseList(Node aNode) {
if (aNode != null) {
reverseList(aNode.next);
System.out.printf("%-15s%6s%n" , aNode.name , aNode.score);
}
}
I created this code, seems like it should be working properly and the code is right, but the output is not what it should be.The action gets a List<Integer> and should make it reversed.
As example: 1 2 3 4 5 ---> 5 4 3 2 1
The Nodes in the new list (lst2) should be in a reversed position.The code does compile with no errors.I do have Node<T> and List<T> classes
Java Code:
public class NodeReverse
{
public static void reverse (List<Integer> lst, Node<Integer> node, int counter, List<Integer> lst2, Node<Integer> pos) // Should make lst = lst2 while lst2 is the opposite to lst
{
node = node.getNext();
counter++;
if(node.getNext()!=null)
reverse(lst, node, counter, lst2, pos);
[code]....
I have the following double linked list and I'm supposed to order it descending (reverse) using the printInReverse() method; since the list orders itself ascending when the numbers are added, how could I order it descending in this method? Here's the code without implementing descending/reversing methods:
package test;
import java.util.Scanner;
public class MyList {
private Scanner userInput;
private Integer selectedOption;
private MyListElement firstElement = null;
private boolean exitRequested = false;
[Code] ....
I tried to declare a previousElement variable but I didn't figure out how I'd do that.
How to implement HashMap put and get methods without using Java Collection framework?
View Replies View RelatedI am writing a game in Java for Android (although my question isn't Android or Game Dev specific).
I have a SceneManager class and a Scene interface and then various other classes that implement the Scene interface (Code at the end of this post).
Basically, in my MainGame class (which also implements the Scene Interface for Touch Event capturing purposes) I hold the bulk of my game code. Methods in this class are then called from my Level classes. (most of these are needed in all levels so it makes sense to hold them here and call them from the levels to eliminate unnecessary code duplication)
So, I have Level1, Level2......... Level20 classes which all implement Scene.
Now, the problem comes because in only 2 of my Levels something can happen (that can't in the other 18) and I need to run a response method in these 2 levels (the method isn't exactly the same, the response to this event happening is different for both levels).
To run common methods from my classes, I use my Scene Manager like this:
SceneManager.getInstance().getCurrentScene().updateLogic();
SceneManager.getInstance().getCurrentScene().render();
(The above is from my gameloop) - So it will run the updateLogic(); and render(); methods from whichever is the current scene (Level).
Scene is changed like so:
SceneManager.getInstance().setCurrentScene(LevelX);
This works great as all Level's have an updateLogic(); and render(); method.
So from my mainGame class, I am doing something like : (pseudo code)
public void checkIfSomethingHappened(){
if (something happens){
if (currentLevel==5){
Level5.response();}
[Code]....
The above would be called from my 2 level classes. So something like:
MainGame.checkIfSomethingHappened(); //Called in addition to the normal methods that make up that level
I don't really want to have this (second) 'if' statement here in the middle of my performance critical game loop.
What I'm after is something like this:
if (something happens){
SceneManager.getInstance().getCurrentScene().response();
}
However, this would require me to put stubs in the other 18 classes.
I'm thinking there must be a way to do this as the SceneManager already knows the current scene so it seems a waste checking it again via an if (or switch) statement. What is the best way to do this without having to put stubs into classes that don't require this method?
Implementing the add(int i, E o) method for a SinglyLinked List.
public void add(int i, E o)
// pre: 0<=i<= size()
// post: adds ith entry of list to o
I'm trying to build a program that contains the ability to:
(1) insert new node at head,
(2) print out contents of the list in order,
(3) remove first node from head,
(4) remove last node from tail,
(5) find a target value,
(6) give total number of occurrences of a target value, and
(7) give total number of items in list.
The areas I'm struggling with implementing are: (
- remove from tail - I know how to find the final node but I can't quite figure out how to set it to null since its initial type is an integer.
- find a target value - how to make the parameters quite workout so the user can simply input an integer value.
- The solution is probably really simple but I can't figure out how to print out the results of these methods when I call them.
public class Node
{
private int data;
private Node link;
// Node Constructor 1
public Node()
{
data = 0;
link = null;
[code]....
I wrote displayAscending() and displayDescending() methods to this double linked list and it is not working at all. Logically it seems fine to me. I positioned the head in the beginning in the ascending method; created a variable named data1 as an auxiliar variable so it can store the values that are going to be moved; and moved the values. Same thing for the descending method but instead of the head I put the tail and move left the list, instead of right.
import java.util.*;
class node {
int data;
node left;
node right;
node(int d, node l, node r) {
data = d;
[Code]...
I am trying to invoke some methods in a for loop in order to print some info stored in a List. But for some reason, compiler pops a message saying "cannot find symbol - method getEmpID(). You are using a symbol here (a name for a variable, method or class) that has not been declared in any visible scope." But I am pretty sure that method getEmpID (as also getName(), getAfm(), and payment() ) have been declared as public.
Note: My List contains objects of different type (SalariedEmployee, HourlyEmployee). I hope this is not the factor causing this problem.
Java Code:
import java.util.*;
abstract class Employee{
private String name = "";
private String afm = "";
private long EmpID;
static long count=0;
[code]....
Is there any way how to reverse a string value without using reverse(),length()?
View Replies View RelatedI need this to print output opposite the way it is. When it reads my file it prints it out like this:
4X^0+3X^1+-2X^2+5X^3+6X^5
But is needs to be this:
6x^5+5x^3+-2x^2+3x^1+4x^0
import java.io.File;
import java.io.FileNotFoundException;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import java.util.Scanner;
import java.util.Iterator;
import java.util.Set;
[code]....
I want to reverse a String that is input
This is what I have tried so far
public class ReverseStringTest {
public static void main(String[] args) {
Scanner in=new Scanner(System.in);
System.out.println("Enter String to replace:");
String temp=in.next();
System.out.println("Reverse String is:"+reverseString(temp));
[code]...
But its not working it is return same string that is Input.
I am trying to reverse a string. Here is my code:
import java.util.*;
public class ReverseLettersInString {
public static void main (String[] args){
Scanner in = new Scanner (System.in);
String s;
[Code] .....
PROGRAM OUTPUT:
Enter string
me
e
The program returns e instead of em
I'm trying to make a piece of code that writes a for Loop program using OOP. I need to create a class, name that class and have it contain several reverse methods and use a runner class to test it.So far this is the code I've come up with. Does it work or not?
public class loopDemo{
public static void main(string[]args){
String alphabet = "abcdefghijklmnopqrstuvwxyz";
public String reverse(){
char myBoi;
int myIta;
String tebahpla
for(myIta=25j i>=0 ji++){
tebahpla+= alphabet.charAt(myIta);
This code is supposed to convert a decimal base number to base 2, 8 or 16. It prints the number but it's supposed to be in the reverse order for example when converting 188 to base 16. it prints CB instead of BC.
package test;
import java.util.Scanner;
public class Test {
public static void main(String[] args) {
Scanner input = new Scanner(System.in);
System.out.println("Enter a positive integer.");
int number = input.nextInt();
[Code] ....
Here is my code:
public class ReverseString {
public static void main(String args[]) {
//quick wasy to reverse String in Java - Use StringBuffer
String str = "The rain in Spain falls mainly on the plain";
String revString = new StringBuffer(str).reverse().toString();
[Code] .....
The requirements: The program runs but for some reason it is not meeting the requirements. use the String method toCharArray and a loop to display the letters in the string in reverse order.
This is how the for loop works for the row,right?
for(int i=array.length-1;i>=0;i--)
{
}
I want to know how the for loop works for the column?
This is what I have to do:Write a program that takes a string of someone's name and prints it out last name first. Your program must use pointers, not array subscripts. You may use the available string manipulation functions if you find an opportunity.
Example:
"George Washington"
"Washington, George"
I am not sure how to reverse the name, I have been looking in my textbook and online and cannot figure it out. This is what I have put together so far, it does not run. At the end it says unnecessary return value.
import java.util.*;
import java.util.Scanner;
public class Test {
public static void main ( String [] args ) {
Scanner sc = new Scanner(System.in);
System.out.print("Enter name: ");
String name = sc.nextLine();
String lastname = "";
String firstname = "";
for(int i = 0; i < name.length(); i++) {
if(name.charAt(i) == ' ')
I want to write an application that inputs a sentence, tokenizes the words with method split and reverse the words (not the letters)...I am stuck at the last part: how to reverse them...should I use the method reverse(); ?
Here is my code..
import java.util.Scanner;
import java.util.StringTokenizer;
public class ReversedWords {
//execute application
public static void main( String [] args) {
//get sentence
[code]....
The code below is running, but when I enter the numbers it shows up with what is just below.
----jGRASP exec: java ReverseOrder
Please enter 5 integers with no spaces in between: 12345
Exception in thread "main" java.lang.StringIndexOutOfBoundsException: String index out of range: 5
at java.lang.String.charAt(String.java:646)
at ReverseOrder.reverseDigits(ReverseOrder.java:30)
at ReverseOrder.main(ReverseOrder.java:15)
[code]....
In this exercise, create a program that asks a user for a phrase, then returns the phrase with the words in reverse order. Use the String class's .split() method for this.
Example input
The rain in Spain falls mainly on the plain
Example output
plain the on mainly falls Spain in rain The
While I understand the assignment, nowhere in the text is it covered how to reverse the order of the words in the string. I understand using the .split method, but not for this exercise.
Here is my code so far.
import java.util.*;
/**
* Java class SplitString
* This program asks for a phrase, and the code allows the phase to return in reverse order.
*/
public class SplitString {
public static void main (String[] args){
//set phrase input and mixed which will be the result
[Code] ....
As you can see, I have been googling this method and have come up nearly empty. My text does not cover the .reverse() method. The only thing it covers with .split() is how to split a string. I also tried StringBuilder with no success.
I'm trying to make this code's output display like a sentence, since right now it displays downward and doesn' look right.
public class ReverseOrder {
public static void main(String[] args) {
String phrase = "The rain in Spain falls mainly on the Plain";
char[] phraseArray;
phraseArray = phrase.toCharArray();
for(int i = phraseArray.length - 1; i >= 0; i--){
System.out.println(phraseArray[i]);
}
} // end main
} // end ReverseOrder class
I am trying to do this assignment but I can't get the needed output. Create a program that asks the user how many floating point numbers he wants to give. After this the program asks the numbers, stores them in an array and prints the contents of the array in reverse order.
Program is written to a class called ReverseNumbers.
Example output
How many floating point numbers do you want to type: 5
Type in 1. number: 5,4
Type in 2. number: 6
Type in 3. number: 7,2
Type in 4. number: -5
Type in 5. number: 2
Given numbers in reverse order:
2.0
-5.0
7.2
6.0
5.4
My code:
import java.util.Scanner;
public class apples {
public static void main(String[] args) {
Scanner reader = new Scanner(System.in);
double[] numbers;
System.out.print("How many floating point numbers do you want to type: ");
[Code] .....
So In my program I have a String called original and I am supposed to prompt the user for a sentence and then Make a StringBuilder instance called “originalReversed” based off of original. Then I have to do is to "Manipulate originalReversed so that it contains the value of original in reverse. This is done with a single statement."
import java.util.Scanner;
public class StringBuilderPractice {
public static void main(String [] args)
{
Scanner input = new Scanner(System.in);
String original;
System.out.println("Please enter a sentence: ");
original = input.nextLine();
}
how to create the instance but not the second part where it says manipulate the value for the first part I think it might be
StringBuilder originalReversed = new StringBuilder(original);