Write a program to find odd number from student roll number

import java.util.*; public class Main { public static void main(String[] args) { System.out.println("Enter the set of students"); Scanner s=new Scanner(System.in); int setn=s.nextInt(); if(setn<=0) { System.out.println(setn+" is an invalid size"); return; } System.out.println("Enter the roll number"); int[] rolls=new int[setn]; int oddflag=0; for(int i=0;i<setn;i++) { rolls[i]=s.nextInt(); if(rolls[i]<0) { System.out.println(rolls[i]+" is an invalid roll number"); return; } if(rolls[i]%2!=0) { oddflag=1; } } if(oddflag==0) { System.out.println("The "+setn+" numbers are not odd"); return; } String str=""; for(int i=0;i<setn;i++) { if(rolls[i]%2!=0) { str=str+rolls[i]; } } for(int n=0;n<str.length();n++) { System.out.println(str.charAt(n)+" "); } } }