import java.io.*;
import java.lang.*;
class stringnumber{
public static void main(String args[])throws IOException
{
int i,a=0,b,n=0,count=0;
String y,kh="0";

/* INPUT FROM THE KEYBOARD */

InputStreamReader obj=new InputStreamReader(System.in);
BufferedReader br=new BufferedReader(obj);
System.out.println("enter the number");
String ch=br.readLine();
a=ch.length();
for(count=0;count<=a;count++)
{
System.out.println(" the num entered is"+"\t"+"\t"+ ch);
System.out.println(" the string length is"+"\t"+ch.length());

/* SPERATING THE STRINGS .CONVERTING THE STRINGS TO INTEGERS.ADDITION OF

THE INTEGERS */

for(i=0;i<a;i++)
{
System.out.println(" the seperated strings

are"+"\t"+ch.charAt(i));
Character c = new Character(ch.charAt(i));
String s = c.toString();
b = Integer.parseInt(s);
n=n+b;
y=Integer.toString(n);
kh=y;
}
n=0;
System.out.println(" the sum is"+"\t"+kh);
ch=kh;
System.out.println(" new string is"+"\t"+ch);
a=kh.length();
System.out.println(" the new length now is "+"\t"+a);
}
System.out.println(" the remaining single digit number is "+"\t"+ch);
}
}

if u don't understand any part , feel free to ask me
bye.