Question

Write a Java method that removes any duplicate elements from an ArrayList of integers. The method has the following header(signature):

public static void removeDuplicate(ArrayList<Integer> list)

Write a test program (with main method) that prompts the user to enter 10 integers to a list and displays the distinct integers separated by exactly one space. Here is what the input and output should look like:

     Enter ten integers: 28 4 2 4 9 8 27 1 1 9

     The distinct integers are 28 4 2 9 8 27 1

Answer 1

// RemoveDuplicates.java
import java.util.Scanner;
import java.util.ArrayList;

public class RemoveDuplicates
{
public static void removeDuplicate(ArrayList<Integer> integerList)
{

ArrayList<Integer> temporaryList = new ArrayList<>();

for (int i = 0; i < integerList.size(); i++)
{
// check for duplicates
if (!temporaryList.contains(integerList.get(i)))
{
// add to temporary list
temporaryList.add(integerList.get(i));
}
}
// clear the integer list
integerList.clear();
// add the temp list to ineter list
integerList.addAll(temporaryList);

}

public static void main(String[] args)
{
Scanner scan = new Scanner(System.in);

int size = 10;
int number;
  
ArrayList<Integer> integerList = new ArrayList<>();

System.out.print("Enter ten integers: ");

for (int i = 0; i < size; i++)
{
number = scan.nextInt();
integerList.add(number);
}

// calling the method
removeDuplicate(integerList);

System.out.println("The distinct integers are " + integerList);
}

}

/*
output:

Enter ten integers: 28 4 2 4 9 8 27 1 1 9
The distinct integers are [28, 4, 2, 9, 8, 27, 1]

*/