ArrayOfCounters

import java.util.Scanner;

public class ArrayOfCounters {

    public static void main(String[] args) {
        Scanner scanner = new Scanner(System.in);
        int input;
        int[] frequencyCounter = new int[51];

        do {
            System.out.print("Enter an integer between 0 and 50, inclusive: ");
            input = scanner.nextInt();
            if (input > -1 && input < 51) {
                frequencyCounter[input]++;
            }
        } while (input > -1 && input < 51);

        for (int i=0; i<frequencyCounter.length; i++) {
            if (frequencyCounter[i] > 0) {
                System.out.println(i + " : " + frequencyCounter[i]);
            }
        }
    }
}