Finding Duplicates in Array and printing them only Once

Question

I am trying to loop through my array and find all the numbers that are repeating more than once:

E.G: if there is 1 1 2 3 4

It should print saying \

Answer 1

This problem is much simpler and likely faster to solve using a collection. However, as requested here's an answer that uses "just simple array[s]" and no sorting. I've tried not to change your code too much but I refuse to leak resources in the case of an exception.

import java.io.*;
import java.util.Arrays;
import java.util.Scanner;

class Average {

     public static void main(String[] args) throws IOException {

        int numOfLines = 0;
        int sum = 0, mean = 0, median = 0, lq = 0, uq = 0;
        int[] buffer;
        int flag = -1;

        File myFile = new File("num.txt");
        try (Scanner Scan = new Scanner(myFile)) {

            while(Scan.hasNextLine()) {
                Scan.nextLine();
                numOfLines++;
            }
        }
        try (Scanner Scan = new Scanner(myFile)) {

            System.out.println("Number Of Lines: " + numOfLines);

            buffer = new int[numOfLines];

            for(int i=0; i

Input file "num.txt" (numbers separated by newlines not commas):

1, 2, 3, 4, 5, 6, 7, 2, 1, 7, 9, 1, 1, 3

Output:

Number Of Lines: 14
Sum: 91
Mean: 6
Dupes: [1, 2, 3, 7]