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I was trying to split a String into a String array using the split function but received the error:

Exception in thread "main" java.lang.NullPointerException
at wdtbam.main(Main.java:16)

I was solving this problem at Codechef. My goal was to split the String into indexes of an array wherever a space was encountered and later parse that into Long type.

Here's my code

import java.util.*;
import java.io.*;
class wdtbam
{
    public static void main(String args[]) throws IOException
    {
        BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
        Scanner sc = new Scanner(br);
        int t =sc.nextInt();
        for(int i=1;i<=t;i++)
        {
            int n =sc.nextInt();
            String a =br.readLine();
            String b =br.readLine();
            String c = br.readLine();
            String cx[]= c.split(" ");  //the problem
            long d []=new long[1234];
            int y=0;
            for(int j=0;j<=n;j++)
            {
                d[j]=Long.parseLong(cx[j]);
            }
            for(int k=0;k<n;k++)
            {
                if(a.charAt(k)==b.charAt(k))
                {
                    y++;
                }
            }
            System.out.println(d[y]);
        }
    }
}

I have been encountering this problem since long and it would be very appcreciable if someone could help me out.

EDIT:

I removed BufferedReader from my code and instead used only Scanner. I also tried to directly input the numbers into an array instead of inputing a string and later parsing it to an long array.

Here's my new code:

import java.util.*;
import java.io.*;
class wdtbam
{
    public static void main(String args[])
    {
        Scanner sc = new Scanner(System.in);
        int t =sc.nextInt();
        for(int i=1;i<=t;i++)
        {
            int n =sc.nextInt();
            String a =sc.nextLine();
            String b =sc.nextLine();
            long d []=new long[1234];
            int y=0;
            for(int j=0;j<=n;j++)
            {
                d[j]=sc.nextInt();
            }
            for(int k=0;k<n;k++)
            {
                if(a.charAt(k)==b.charAt(k))
                {
                    y++;
                }
            }
            System.out.println(d[y]);
        }
    }
}

I am still getting an error. IDK why. Please help I am really frustrated with JAVA right now.

Error:

Exception in thread "main" java.util.InputMismatchException
    at java.util.Scanner.throwFor(Scanner.java:864)
    at java.util.Scanner.next(Scanner.java:1485)
    at java.util.Scanner.nextInt(Scanner.java:2117)
    at java.util.Scanner.nextInt(Scanner.java:2076)
    at wdtbam.main(Main.java:18)

BTW here's the problem I was trying to solve : Codechef

Suryansh Singh
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    I don't see the need for the BufferedReader... Just use `Scanner sc = new Scanner(System.in)` and `sc.nextLine()` – OneCricketeer Jul 31 '16 at 19:55
  • The problem is that you are reading too many lines of input. `br.readLine();` returns null when the stream has ended – OneCricketeer Jul 31 '16 at 19:59
  • This exception is strange here since `br` is reading `System.in` which should be opened (I don't see any closing statements). So `readLine` couldn't return `null` which could cause NPE. – Pshemo Jul 31 '16 at 20:08
  • I see that the question is marked duplicate, I tried to understand the [What is a NullPointerException, and how do I fix it?](http://stackoverflow.com/questions/218384/what-is-a-nullpointerexception-and-how-do-i-fix-it) but couldn't successfully find an implementation relevant to my case. I mean how will I implement that solution in my particular case (Please Tell). – Suryansh Singh Aug 01 '16 at 18:45
  • I tried what all is mentioned by @cricket_007 but it returned the same error. – Suryansh Singh Aug 01 '16 at 18:46

0 Answers0