How to create a program that allows user to decide the number of Scanner input and then divides Scanners into arrays of positive and negative numbers?

Question

package nizovi;

import java.util.Scanner;

public class Nizovi {

private static String array;


public static void main(String[] args) {
    Scanner sc= new Scanner (System.in);
    int k = sc.nextInt();
    int[] pos =new int[k];
    int[] neg = new int [k];
    Scanner n= new Scanner (System.in);
    System.out.println("Enter the number of members of array:");
    int members = n.nextInt();
    for (int i=k;i>0;){
         Scanner numb= new Scanner (System.in);
          System.out.println("Enter number:");
          int num=numb.nextInt();
          if (broj >=0){
              pos[num]=n.nextInt();

          }
          else{
              neg[num]=n.nextInt();


          }
    }
}
}

I am using for loop and I am confused how to add more numbers into it because if I leave array command in for loop it defines it every time with the different scanner.Sorry for the bad explanation.

Answer 1

First: use one Scanner per input source, so here just one not 3

Then, you need to it by steps, you do a lot of useless things

• ask the number of numbers you want to input k
• create the arrays
• ask k times the user to input a value
• from the value insert in one array of the other

But you'll have zeros in your array, because you create 2 arrays of size k but enter only k elements, so you'll have k zeros in total in your arrays, use List to have only what you need

Scanner scanner = new Scanner(System.in);
System.out.println("Enter the number of members of array:");
int k = scanner.nextInt();

int[] pos = new int[k];
int[] neg = new int[k];

for (int i = 0; i < k; i++) {
    System.out.println("Enter a number:");
    int numberUser = scanner.nextInt();
    if (numberUser > 0) {
        pos[i] = numberUser;
    } else {
        neg[i] = numberUser;
    }
}
System.out.println(Arrays.toString(pos));
System.out.println(Arrays.toString(neg));

Answer 2

Scanner numb= new Scanner (System.in);

That statement... is simply useless.

You already defined a valid scanner once, further up, named n .

You only should:

• use a more meaningful name, like scannerForUserInput instead of n .
• and then, whenever you want to read from the uer, you use that instance.

There is simply no need to define a new scanner for each new input data.