My goal is to generate random number from 0 to 100 and add them into a linkedlist object and then sort the elements.
This is my code so far. I'm running into problems when I want to display the sorted elements.
The error I get: Exception in thread "main" java.util.IllegalFormatConversionException: d != java.util.Arrays$ArrayList
Can someone throw some light into this problem? Thank You
package com.LinkedLists;
import java.util.Arrays;
import java.util.Collection;
import java.util.HashSet;
import java.util.List;
import java.util.LinkedList;
import java.util.Random;
import java.util.Set;
public class InsertRandomElements {
public static void main(String[] args) {
// Create a random number object from 0 to 100.
// Create an array object.
Random r = new Random();
int[] random = new int[100];
// Insert random numbers into the array
for (int i = 0; i < random.length; i++) {
random[i] = r.nextInt(100) + 1;
}
// Printing out the unsorted array
for (int i = 0; i < random.length; i++) {
System.out.println(random[i]);
}
List<int[]> randomList = Arrays.asList(random);
// Call the method in here.
sortElements(randomList);
}
// Sort the elements
private static void sortElements(Collection<int[]> values) {
Set<int[]> set = new HashSet<int[]>(values);
for (int[] is : set) {
System.out.printf("Sorted Elements: %d ", values);
}
System.out.println();
}
// Calculate Sum of the elements
// Calculate floating point average of the elements.
}
You need a List<Integer>
and not a List<int[]>
. Converting from a primitive array into a list of Integers is not a one-call operation, you'll actuall have to iterate over the primitive array and add to the list one by one. I don't recommend this, especially since there is no reason to use the array in the first place. For reference, you need this:
final List<Integer> randomList = new LinkedList<>();
for (int i : random) randomList.add(i);
When you change that, this will work:
System.out.printf("Sorted Elements: %s ", values);
However, it would be much simpler to sort the array itself using Arrays.sort(myArray)
and then print using
System.out.println(Arrays.toString(myArray));
On the other hand, if you used a List<Integer>
right from the start, it would look like this:
final Random rnd = new Random();
final List<Integer> values = new ArrayList<>();
for (int i = 0; i < 100; i++) values.add(rnd.nextInt());
Collections.sort(values);
System.out.println("Sorted Elements: " + values);
Its getting confused because ** int[]
is an object but int
is not so it assumes int[]
as one element of the List
, and hence returning List<int[]>
not List<Integer>
or List<int>(this is not possible and is causing the issue)
.
Please change your random to Integer[]
as below, it should work fine.
Integer [] random = new Integer[100];
List<Integer> randomList = Arrays.asList(random);
To sort the list: Use Collections#sort
Collections.sort(randomList);
Please remember , the method signature is: public static <T> List<T> asList(T... a)
which determines the type of List to be returned based on the argument type being passed.
Please Note: Even when you define random
as new Integer[100];
, still you can leave this kind statements as is: random[i] = r.nextInt(100) + 1;
. This works fine as int
is promoted to Integer
in those cases.
In this case, I think it would be easier to pass the random
array directly to a sortElements(int[] values)
method and then convert the array to a list.
In other words, you would call sortElements(random);
and then List<Integer> randomList = new LinkedList(Arrays.asList(random));
to get a linked list.
Using your code try:
for (int[] is : set) {
System.out.printf("Sorted Elements: %d ", is[0]);
}
but you still need to sort it, as mentioned in previous post
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