(';' expected boolean checkBinary(String num) {^) Need help finding the error

Question

i keep getting a ';' is expected at the checkBinary(String num) { ^ error, yet i can't find any place for a ";". I have only been studying java for a few days so the problem could be something obvious i haven't learnt yet. Please provide a detailed explanation in way i could use it to prevent the problem in later projects. Thank you in advance!

import java.io.*;
import java.util.Scanner;

public class checkbinary
{
public static void main(String[] args)
{
    String num;
    System.out.println("Enter a number:");
Scanner sc = new Scanner(System.in);
num = sc.nextLine();
   if(checkBinary(num)) {
       System.out.println("The number is: Binary");
   } else {
       System.out.println("The number is: Not Binary");
   }

    boolean checkBinary(String num) {
       for(i=0;i<num.length();i++) {
           digit = Integer.parseInt(num.substring(i,i+1));
           if(digit > 1) { 
               return false;
           }
       }
       return true;
   }

}

method inside method is not allowed – jmj Aug 12 '15 at 20:53 — jmj, Aug 12 '15 at 20:53

score 1 · Accepted Answer · edited May 23 '17 at 11:51

You need to move your checkBinary method outside of the main method. You cannot nest methods in java without declaring an inner class.

This should work:

import java.io.*;
import java.util.Scanner;

public class checkbinary
{
    public boolean checkBinary(String num) {
        for(i=0;i<num.length();i++) {
            digit = Integer.parseInt(num.substring(i,i+1));
            if(digit > 1) { 
                return false;
            }
         }
         return true;
    }

    public static void main(String[] args)
    {
        String num;
        System.out.println("Enter a number:");
        Scanner sc = new Scanner(System.in);
        num = sc.nextLine();
        if(checkBinary(num)) {
            System.out.println("The number is: Binary");
        } else {
            System.out.println("The number is: Not Binary");
        }
    } 
}

If you want to know how to go about solving this with a nested class, there are numerous other questions/examples on SO. Like this one Can methods in java be nested and what is the effect? or In java what are nested classes and what do they do?

Thanks for the info, this is exactly what i was looking for. — Louis Syropoulo, Aug 13 '15 at 00:15
@LouisSyropoulo If this solved your problem, don't forget to "accept" it as the answer! — jkeuhlen, Aug 13 '15 at 14:03

(';' expected boolean checkBinary(String num) {^) Need help finding the error

1 Answers1