Sorting Arrays In Descending Order With Collections Class
Jun 28, 2014
I am trying to create a java program to sort an array in ascending and descending order. Here is the program I created :
import java.util.Arrays;
import java.util.Collections;
public class ArraySort
{
public static void main(String [] args) {
int [] num = {5,9,1,65,7,8,9};
Arrays.sort(num);
[Code]...
BUT I GET THE FOLLOWING EROOR ON COMPILATION
ArraySort.java:12: error: no suitable method found for reverseOrder(int[])
Arrays.sort(num,Collections.reverseOrder(num));
^
method Collections.<T#1>reverseOrder(Comparator<T#1>) is not applicable
[Code] .....
What's wrong with my program?
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Apr 10, 2014
I am sorting an array in ascending and descending order. I am using the nethods in Arrays as below
Arrays.sort(myArray)
I want to print both input and output array in sysout.
Object[] ipArray = [45,8,32,41,11,7];
Object[] opArray;
Object mArray = ipArray;
Arrays.sort(mArray); This is changing the ipArray too ?
How can I get my input array unmodified ?
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Oct 15, 2014
I am writing a program that grab user input number which represent beats per minute separated by commas. It then parses the numbers and reorders them from smallest to largest and then outputs the average, medium, maximum and minimum number all in separate lines. I am having trouble getting the array to sort the input from smallest to largest. It is currently only working for 3 numbers inputted. Anything more will not reorder it.
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package heartrate;
import java.util.Scanner;
import java.util.Arrays;
[Code] ....
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Feb 12, 2014
These are all arraylists and not arrays
I have currently two arrays.
Java Code:
String[] chunks = {"a","b","c"};
int[] freq = {2,4,3}; mh_sh_highlight_all('java');
I am looking for a way to order these from greatest to smallest based on frequency.
The resulting arrays should be:
Java Code:
chunks = {"b","c","a"};
freq = {4,3,2}; mh_sh_highlight_all('java');
Because b is most frequent, and a is least frequent.
One way I can think of doing this is a two dimensional String array
Java Code: String[][] fullHold = {{"b","c","a"},{"4","3","2"}}; mh_sh_highlight_all('java');
Then sort based on the character values of the second row.
How can I sort a two dimensional array based on a single row (where it will rearrange the other rows in accordance).
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Jul 4, 2014
I have never seen a class defined under another class ....
class pe{
static class pqsort implements Comparator<integer>
public into compare(Integer one,Integer two)
return two-one;
}
}
First I want to know how class pqsort is defined under class pe ....
And how the comparator used in this example is sorting elements in reverse order
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Oct 7, 2014
I am working on descending after I assign values. And everything is sorted, but one value. I don't know why always I get one value is not sorted.
public class SeunghunJunHw6 {
public static void main(String[] args){
double[] randomArray = new double[9];
//assign random double values between 0 to 100 but exclude 100
for(int i = 0; i<randomArray.length;i++){
randomArray[i] = Math.random()*100;
[Code] ....
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Sep 12, 2014
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.
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Jun 13, 2014
How to input 10 integer elements in an array & sort them in desc. order using the bubble sort technique.
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Sep 12, 2014
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]...
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Nov 23, 2014
I had to make a program that allowed the user to enter the number of students and the students names and grades and then print out the name with the grade in descending order. right now I only have it where it prints the names out in descending order. how do I get it the print out with the grade?
Here is my code
import java.util.*;
public class Grades {
public static void main(String[] args) {
Scanner input = new Scanner(System.in);
System.out.print("Enter the number of students: ");
int numofstudents = input.nextInt();
[Code] .....
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Oct 24, 2014
I am trying to find the longest descending sequence without arrays. So 65124976231 would output 9762.
import java.util.*;
public class HelloWorld {
public static void main(String[] args){
String num = "";
int longestLen = 0;
int currLen = 0;
String max = "";
[Code]...
I keep getting: The longest descending sequence is: 6512 In an infinite loop.
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Apr 6, 2014
I have searched on internet but did not find something useful. I do not want to use collections. here's what i have written
class ArrayDemo3
{
static void union(int x[], int y[])
{
System.out.println("Union Elements:");
for(int i=0; i<x.length; i++)
{
for(int j=0; j<y.length; j++)
[code]....
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Jan 10, 2014
My friends and me are trying to make online Test taking system. We got a very basic doubt.
We have developed classes and relationship between classes for example : Online Test Taking system will have admin and student class. And Admin will have list of students.. etc.
But question troubled me was: if we use database to store all data for example student details then I can perform all sorts of operations writing sql query and store result in some other database then what is the need of "ArrayList<Student> field in Admin".??
Question is: We can put everything in database and manipulate using database(sql) functions to manipulate it.Then what is the need of Arraylist of anything which is just used to store object details for example student details....??
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Feb 3, 2015
I am trying to sort an array that I have by alphabetical order but I am having problems. Firstly the code that I have used to sort the array may not even do what I need but havn't got far enough to test it yet so go easy on me . I have read in some places when searching how to do this that I would have to create my own bubble sort in order to achieve this but I was hoping that Java had a built in sort method/function. Secondly I lack the knowledge in java to be able to assign an existing array or even a variable to the newly sorted array as I need the unsorted version with the original name and the newly sorted version as another.
code (This is not all of the code, I decided to include only what I thought was relevant):
import java.util.Arrays;
public class Sentence {
private String words[];
public Sentence(String[] words) { this.words = words; }
@Override
public String toString() {
return "Sentence{" +
"words=" + Arrays.toString(words) +
[Code] ....
Is it possible to shorten the sort function to just this?
public String sorted() {
return Arrays.sort(words);
}
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May 5, 2014
i need to sort these runners into time order shortest first, the classes both work i just cant get the method sortRunnerList() to work
Java Code:
public class Runner implements Comparable <Runner>
{
/* static variables */
private static int nextNumber;
// To be added by students in Question 3, part (i)(a) and part(iv)(a)
/* instance variables */
private int number; // runner's number
private String name; // runner's name
[Code] .....
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Feb 24, 2014
The Iteratior provides the functionality of traversing and removal which we can achieve through normal for loop and remove() of the data structure.Then, why do we need Iterator explicitly and as an inner class?
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Nov 12, 2014
I am writing a program that is supposed to take 3 numbers inputted by the user and sorting them out in an ascending order. I believe my code is correct but can't figure out why the program isn't behaving as expected.
import java.util.*; //Required to use the scanner console
public class Week3_Programming_Problem
{
static Scanner console = new Scanner(System.in); //Allows for user input
public static void main(String[] args)
[code]....
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Oct 21, 2014
I couldn't where the problem with this code. The question is : (Write a program that reads in nine integers and sorts the value in the ascending order. Next, the program restores the sorted integers in a 3 x 3 two-dimensional array and display the integers as shown in the result.) And this how i did it:
package test1;
import java.io.*;
import java.util.*;
public class test1{
public static void main(String[] args){
int[] hold = new int [9];
Scanner sc = new Scanner(System.in);
System.out.print("Enter 9 integers, press <Enter> after each");
{
for (int i = 0; i < hold.length; i++);
[Code] ....
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Sep 17, 2014
I'm trying to sort 10 inputted numbers (double precision) using the Array.sort() method. I can get the 10 numbers inputted, but the output is ten 0.0s; now (and this how I know I am learning some things) I'm fairly certain that the variable number is not storing the numbers inputted by the user otherwise I wild be seeing the program work correctly.
So my question is why isn't number storing the inputs?
import javax.swing.JOptionPane;
import java.util.Arrays;
public class KrisFrench3 {
public static void main(String[] args) {
double[] number = new double[10];
for(int i = 1; i <= i; i++) {
[Code] .....
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Jul 1, 2014
Write a method called isSorted that accepts an array of real numbers as a parameter and returns true if the list is in sorted (nondecreasing) order and false otherwise. For example, if arrays named list1 and list2 store {16.1, 12.3,22.2, 14.4} and {1.5, 4.3, 7.0, 19.5, 25.1, 46.2} respectively, the calls is Sorted(list1) and isSorted(list2)should return false and true respectively. Assume the array has at least one element. A one-element array is considered
to be sorted. public class thirfd {
public static void main(String[] args) {
double[] arr1 = {16.1, 12.3,22.2, 14.4};
double[] arr2 = {1.5, 0.3, 7.0, 19.5, 25.1, 46.2};
isSorted(arr2);
System.out.println(isSorted(arr2));
[code]...
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Nov 2, 2014
My code is not working properly. The ascending and descending numbers are not showing up. I believe what it is printing is the memory location. In this lab you will be coding a program that will make use of functions to search and sort an array. There will also be a print method, again complete with a full menu system. The Menu options are listed below in the section labeled menu.You will need to set up a hundred (100) position integer (int) array that is defined in main. You will also need an integer (int) variable called size. By doing this, you will have to pass the array and the size to each method you write.
Menu:
The menu should have the following eight options:
1. Fill the array with random numbers (1 -100)
2. Print the array
3. Sort the array in ascending sequence
4. Sort the array in descending sequence
5. Sequential search of the array for a
6. Binary search of the array for a target
7. Exit (this can be option zero if you prefer)
From these seven Options, one can see that six methods will be needed. Each of the six main functionalities above will need a function that does what they say. When printing the array, it is required to print the position number alongside the value. Please start your positions at zero, and not one. When doing the sorting methods, please use two different sorting algorithms. (ie, use a Min Max sort for ascending and an enhanced bubble for descending.)
For the Searching methods: you should ask for the target (number the user is searching for) in the dispatch method. Then pass the target to the search method. The search method should return the position it was found at (0 - Size) OR -1 if it was not found. Then have the appropriate messages print inside of the dispatch method.You could write another function that does this part if you wish to keep your dispatch method cleaner and more organized. But that is up to you.
import java.util.Arrays;
import java.util.Scanner;
import java.util.Random;
public class Lab9 {
public static void main(String[] args)
{
Scanner scan = new Scanner(System.in);
int [] values = new int [100];
[code]....
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Jul 14, 2014
I am confused with the following function signature in the class java.util.Collections.
static <T> boolean replaceAll(List<T> l, T oldValue, T newValue);
I got the other parts but i could not figure out at all what is the meaning of <T> in the beginning.
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Mar 23, 2014
I am currently working on Project which involves me needing a BigInteger array and sorting it somehow. I have been able to do
* Array.sort(arrayname); *
In past codes, but Eclipse is telling me that I can't do this with my BigInteger array. I have already imported java.util.Arrays
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Nov 2, 2013
I need to modify modules used in the book that run a bubble sort, selection sort, and insertion sort on an integer array such that each module keeps a count of the number of swaps it makes.
How do I code for this?
Then we have to design an application that uses 3 identical arrays of at least 20 integers. That calls each module on a different array, and display the number swaps made by each algorithm.
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Oct 12, 2014
I am new to using arrays. I need to collect user input for book title, author, and # of pages... store that in an array... and then I'm going to need to be able to sort that array. The dialog boxes come up prompting the user for 5 sets of title, author, and # of pages, but when I try to display that information, it isn't working. I am assuming this means that it's not storing the information correctly... so I want to get this corrected before I even try to sort??
import javax.swing.*;
import java.util.*;
class LibraryBookSort
{
public static void main(String[] args)
{
LibraryBook[] someBooks = new LibraryBook[5];
[Code] ....
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Oct 17, 2014
im having an issue with the 3rd thread that are supposed to merge the two sorted sub arrays , i pass the 2 subarrays to my runnable function sortlist and they are renamed IntSortList 1 and 2 and th1.start() and th1.join() are called and it works fine, but then i have another runnable constructor that takes IntSortList 1 and 2 but it does take a runnable. below is the code in my main,
Runnable InSortlist1 = new sortList(data2p1);
Runnable InSortlist1 = new sortList(data2p1);
Thread th1 = new Thread (IntSortlist1);
Thread th2 = new Thread (IntSortlist2);
try
{
th1.start();
th1.join();
[code]....
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