Error while getting integer from file(Convert String to Int)

Question

I have a file: student.txt

1      Adam     50       50       50

2      Eric     34       28       38

3      Joash    44       48       49

4      Bill     34       30       45

I have 2 classes: 1 is main and another one does all the work.

// Class 1 ******************

public class Main {
    public static void main(String[] args) {
        readfile a = new readfile();
        a.openFile();
        a.readFile();
        a.closeFile();
    }
}

// ********* Class 2

import java.util.*;
import java.io.*;
import java.lang.*;

public class readfile {

    private Scanner x;

    public void openFile(){
        try{
            x = new Scanner(new File("student.txt"));

        }
        catch(Exception e){
            System.out.println("Error");
        }
    }
    public void readFile(){
        int a=0;
        String b;
        int c=0;
        int d = 0;
        int e = 0;
        int total;
        while(x.hasNext()){
             a = x.next();
             b = x.next();
             c = x.next();
             d = x.next();
             e = x.next();
             int total = c+d+e;
             total = x.nextInt();
            System.out.printf("%s %s %s %s %s %s/n",a,b,c,d,e,total);
        }
    }
    public void closeFile(){
        x.close();
    }
}

I have 2 errors:

1) This is at a = x.next(); where it says

Can't convert from String to int.

Can you tell me how to fix that?

2) This is at:

Exception in thread "main"

Error java.lang.NullPointerException

How do I fix this?

Why do this int total = c+d+e; and then change it in the next line anyway with this total = x.nextInt();? — takendarkk
– takendarkk, Commented Aug 2, 2014 at 2:46

Nabin · Accepted Answer · 2014-08-02 02:34:07Z

1

Try:

a = Integer.parseInt(x.next());

Instead of

a = x.next();

And you may try using

a = x.nextInt();

edited Aug 2, 2014 at 2:34

answered Aug 2, 2014 at 2:10

Nabin

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5 Comments

takendarkk Over a year ago

Why not just use x.nextInt()?

takendarkk Over a year ago

Because then you don't have to use the extra code of Integer.parseInt() for no reason.

Hikkup Over a year ago

Why am i still getting an error at the line: int total = x.nextInt(); ??

Nabin Over a year ago

O God! Try total = Integer.parseInt(x.next()); too

Nabin Over a year ago

You should do basic at first :-)

Rabbyte · Accepted Answer · 2014-08-02 02:13:46Z

1

Scanner.next() returns the next token as a String. When java tries to set int a to a String, an error occurs. You can fix this by using Scanner.nextInt(), which will return the next token as an integer, or throw an error if the next token is not an int. If

answered Aug 2, 2014 at 2:13

Rabbyte

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