Dividing large number into separate digits and store them

Question

So if I for example have a large number, say 18750409. I would like to divide this number into separate digits to 1,8,7,5,0,4,0,9. But I don't want to print them out right away, I would like to store them somewhere, like a number A for 1, number B for 8. (In an array possibly?) So I can do more things with these numbers later in the program before printing out results.

Any help is appreciated!

Do you want to store them as chars or ints (or another number type)? — Java Man Tea Man, Feb 21 '16 at 16:12
My approach would be to divide it into separate chars, and then convert those chars to number types (not cast!) — Java Man Tea Man, Feb 21 '16 at 16:13
Would like to store them as ints if possible, but I guess chars would work to — Gabc, Feb 21 '16 at 16:13
I did look at that first one you linked @Tom but from the answers I saw they printed it out directly. I want to store them and do more operations with these separate numbers — Gabc, Feb 21 '16 at 16:15
Then just don't add the `System.out.println` line in your code... — Tom, Feb 21 '16 at 16:16
When you said you had a large number I thought you mean it has 18750409 digits. An `int` can store this number and I would leave it as an `int` for as long as possible and only turn it into digits for displaying purposes. — Peter Lawrey, Feb 21 '16 at 17:03

score 1 · Accepted Answer · answered Feb 21 '16 at 16:33

1) Get the length (# of digits) of your number (can be done by converting the number to a string and getting the length by calling .length();

int number = ...;
String my_string = "" + number;
int numberLength = my_string.length();

2) Use a for loop to cycle through your string, and make a separate array of characters and as you go through each char of your string using charAt(), store them in that array:

char[] charArray;
charArray = new char[numberLength];

for(int i = 0; i < (numberLength - 1); i++) // -> Remember, -1 because arrays start at 0!
{
  charArray[i] = my_string.charAt(i);
}

Now you have an array of the digits in char form. To convert them back into ints, just cycle through that array and convert the char back to a number. Note: you can also store the digits as strings.

If you are using chars, to convert to int: use getNumericValue() -> this technically returns unicode numerical value, but unicode of a digit is that digit.

int[] digitArray;
digitArray = new int[numberLength];

for (int i =0; i< numberLength; i++)
{
 digitArray[i] = charArray[i].getNumericValue();
}

And thats it. :) (Sorry if some of the java syntax is off; I have not done java in quite some time.

score 0 · Answer 2 · edited Mar 19 '17 at 15:05

package test;

import java.lang.reflect.Array;
import java.util.ArrayList;
import java.util.Scanner;

/**
 *
 * @author shalom
 */
public class Test {

    /**
     * @param args the command line arguments
     */
    public static void main(String[] args) {
        int num,
        temp,     //it holds the remainder value
        n;        //it will be used for seperating the integer
        int[] array;
        String s = "";    // if you want to store the number in string
        System.out.println("Enter the number"); //Taking value from user for any number
        num = new Scanner(System.in).nextInt();

        n = num;

        while (n>0) {
            temp = n%10; //remainder extracted
            s = temp + s;  //concatenated with s
            n = n / 10;    //to get the next digit to be separated

        }

        array = new int[s.length()];    //finally if you want to store the values in array initiliaze the array with lenght of s

        for (int i = 0; i < s.length(); i++)
            array[i] = Integer.parseInt("" + s.charAt(i)); // values are stored in array
    }
}

Please add explanation to your code, rather than just posting an entire program. — Java Man Tea Man, Feb 21 '16 at 16:37

score 0 · Answer 3 · answered Feb 21 '16 at 16:25

You can use ArrayList to store results. And retrieve individual digit i using digitArray.get(i-1)

int n = 18750409;
List<Integer> digitArray = new ArrayList<>();
while(n > 0 ){
  digitArray.add(n%10);
  n = n/10;
}

//to get individual digits
digit3 = digitArray.get(2);

score 0 · Answer 4 · answered Feb 21 '16 at 16:27

  int hjk=326543;
  String cvbn = new String(String.valueOf(hjk));
  System.out.println(cvbn);
  char xcv[] = cvbn.toCharArray();
  int cv[] = new int[xcv.length];
  for(int hj = 0;hj<xcv.length;hj++)
  {
      cv[hj] = Integer.parseInt(String.valueOf(xcv[hj]));
  }

Hope my code helps. Happy coding

Dividing large number into separate digits and store them

4 Answers4