CODEWITHSUNDEEP
javajava.util.scannerbufferedreader
Rishi Dua
Rishi Dua

Reputation: 2334

BufferedReader giving non-zero exit code

Problem A simple programming question, involves reading a number N, T times from console and perform simple calculation on it.

Constraints:

1 ≤ T ≤ 1000

2 ≤ N ≤ 100000000

As BufferedReader is usually faster than Scanner, I used it but the program exited with Non-Zero Exit code whereas using Scanner resolved the issue.

Since both work fine on my computer, I suspect this is a memory issue.

Questions:

  1. Is my assumption that BufferedReader is faster than Scanner correct?
  2. Does BufferedReader use more memory? If yes, is it the reason for the error?

Code:

Using BufferedReader, throws error

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;

public class Main {
    public static void main(String[] args) throws IOException{
        BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
        int T = Integer.parseInt(br.readLine());
        for (int i=0; i<T; i++) {
            int N = Integer.parseInt(br.readLine());
            int res = (N/2)+1;
            System.out.println(res);
        }
        br.close();
    }
}

The code using Scanner that returned correct output:

import java.io.IOException;
import java.util.Scanner;

public class Main {
    public static void main(String[] args) throws IOException{
        Scanner sc = new Scanner(System.in);
        int T = Integer.parseInt(sc.nextLine());
        for (int i=0; i<T; i++) {
            int N = Integer.parseInt(sc.nextLine());
            int res = (N/2)+1;
            System.out.println(res);
        }
        sc.close();
    }
}

Upvotes: 7

Views: 1886

Answers (3)

De Smulmeister
De Smulmeister

Reputation: 29

I had the same error you're having(an error on the BufferedReader). It's because you forgot to put the BufferedReader in a try catch block. I also had the throws IOException after the main funtion but that's not enough. So it's not a memory issue.

The correct code could be something like this:

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;

public class Main {
    public static void main(String[] args) throws IOException{

        BufferedReader br = null;
        try {  
             BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
             int T = Integer.parseInt(br.readLine());
             for (int i=0; i<T; i++) {
             int N = Integer.parseInt(br.readLine());
             int res = (N/2)+1;
             System.out.println(res);
        }catch(Exception e) {
             e.printStackTrace();
        }finally{
             try{
                 br.close();
             }catch ( Exception e){
                 e.printStackTrace();
             }
        } // end of try catch
    }
}

Good Luck!

Upvotes: -1

Ajk_P
Ajk_P

Reputation: 1874

  1. As of JDK 7, BufferedReader uses a bigger buffer than Scanner (I think 8192c vs 1024c), so yes it uses more memory, and can make for a faster runtime on large inputs.
  2. This might be the source of your problem (or it might be that whoever wrote the tests for this problem has something wrong), since I tested your BufferedReader code myself and cannot see any problems with it.

Upvotes: 3

user207421
user207421

Reputation: 311054

Is my assumption that BufferedReader is faster than Scanner correct?

Not in this case, as the speed of your program is limited by how fast you can type. Compared to that, any difference between Scanner and BufferedReader is insignificant.

Does BufferedReader use more memory?

It isn't specified.

If yes, is it the reason for the error?

Is it the reason for what error? As you didn't post the error you're getting, this question is unanswerable. However I don't see any reason to believe you have a memory problem.

Upvotes: 1

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