printing distinct numbers java

Question

I am having a hard time with this code. The code is finished but the output is wrong. My code prints Enter ten numbers: 1 2 3 5 6 6 8 7 4 1 It should print The distinct numbers are: 1 2 3 5 6 8 7 4 but it doesn't. It prints: 10 10 10 10 10 7 How can I fix it?

 Here is my code: import java.util.*; public class homework1 { public static void main(String[] args){ // input from user Scanner input = new Scanner(System.in); int [] numbers = new int[10]; boolean[] distinct = new boolean[10]; System.out.println("Enter ten numbers"); for (int i=0; i<numbers.length; i++){ System.out.println("Number " + (i + 1) +": "); numbers [i] = input.nextInt(); distinct[i] = true; for(int j = 0;j<10; j++){ if(numbers[i] == numbers[j] && i != j) { distinct[i] = false; } } } int count=0; for(int j = 0;j<10; j++){ if (distinct[j]){ numbers[count]=distinct.length; count++; } } System.out.println("The number of distinct number is: "+numbers[count]); System.out.println("The distinct numbers are: "); for(int i= 0; i < 10; i++) { if(distinct[i]) { System.out.print(numbers[i] + " "); } } System.out.println(); } }

Answer 1

This line:

numbers[count]=distinct.length;

Is setting your outputs to be the length of the array (Which in this case is hard coded to 10. Try:

int count=0;
for(int j = 0;j<10; j++){
    if (distinct[j]){
        numbers[count]=numbers[j];
        count++;
    }
}

Which will set your output to be the distinct number.

Plug: Check out Code Review

Answer 2

This will solve your problem. If you use HashMap, you will have less code.

import java.util.HashMap;
import java.util.Iterator;
import java.util.Scanner;
import java.util.Set;

public class Test {

    public static void main(String[] args) {

        HashMap<Integer, String> distinctNumbers = new HashMap<Integer, String>();
        // input from user
        Scanner input = new Scanner(System.in);
        System.out.println("Enter ten numbers");
        for (int i = 0; i < 10; i++) {
            System.out.println("Number " + (i + 1) + ":  ");
            Integer numberEntered = input.nextInt();
            distinctNumbers.put(numberEntered, null);
        }

        System.out.println("The number of distinct number is: " + distinctNumbers.size());
        System.out.println("The distinct numbers are: ");
        Set<Integer> keys = distinctNumbers.keySet();
        for (Iterator<Integer> iterator = keys.iterator(); iterator.hasNext();) {
            Integer integer = (Integer) iterator.next();
            System.out.print(" "+ integer);

        } 
    }

}

Answer 3

Remove line numbers[count] = distinct.length; This make your output are all 10

Then, I change your code a little to make it run right:

...
int count = 0;
    for (int j = 0; j < 10; j++) {
        if (distinct[j]) {
            //numbers[count] = distinct.length; //remove it, it nonsense 
            count++;
        }
    }
// distinct number should be count, not number[count]
System.out.println("The number of distinct number is: " + count);
    ....

Answer 4

public static void main(String[] args) {
        int arr[] = {1,3,5,4,7,3,4,7};
        Map<Integer, Integer> frequency = new HashMap<Integer, Integer>();
        for(int i = 0; i < arr.length; i++) {
            if(frequency.containsKey(arr[i])){
                int value = frequency.get(arr[i]);
                frequency.put(arr[i], value + 1);
            }
            else {
                frequency.put(arr[i], 1);
            }
        }
        for(Map.Entry<Integer, Integer> entry : frequency.entrySet()) {
            System.out.println(entry.getKey());
        }
    }

Answer 5

package Chapter7;

import java.util.Scanner;

public class Exercise7_5 {

    public static void main(String[] args) {
        // Print distinct numbers

        Scanner input = new Scanner(System.in);
        int[] numbers = new int[10];

        System.out.println("Enter 10 numbers:  ");
        for (int i = 0, j = 0; i < 10; i++) {
            if (storeDistinctNumbers(j,input.nextInt(), numbers))
                j++;
        }

        for (int i = 0; numbers[i] != 0 ; i++)
            System.out.print(numbers[i] + " ");
    }

    public static boolean storeDistinctNumbers(int j, int num, int[] numbers) {
        for (int e: numbers) {
            if (e == num)
                return false;
        }
        numbers[j] = num;
        return true;    
    }
}