Design an algorithm for finding all the factors of a positive integer. for example, in the case of the integer 12, your algorithm should report the values 1, 2, 3, 4, 6, and 12

As I say to every one requesting programming help on these forums. If you don't specify a language, then it just means you'll have to translate the answer that is given to you, to a different language. Here's what you want in Java:

import java.util.InputMismatchException;
import java.util.Scanner;

public class Test {
    public static void main(String[] args) {
        int number = numInput();
        printFactors(Math.abs(number));
    }

    private static int numInput() {
        Scanner sc = new Scanner(System.in);

        System.out.print("Enter number: ");

        int input;
        while (true) {
            try {
                input = sc.nextInt();
                break;
            } catch (InputMismatchException e) {
                System.out.println("Not a number.");
            }
        }

        return input;
    }

    private static void printFactors(int number) {
        if (number == 0) {
            System.out.println("Infinite factors.");
        } else {
            for (int i = 1; i <= number; i++) {
                for (int j = 1; j <= number; j++) {
                    if (i * j == number) {
                        System.out.print(i + ", ");
                    }
                }
            }
        }
    }
}