Question

I have made a simple program with :
working with files(read write)
end class extends
but the program does not work. Netbeans show no errors but when i run it ……some kind of errors show up …..and well i can’t understand where is my bug (i think is a logical one).

Here is the simple program:

package detyre_kursi;

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

public class Detyre_kursi {

  public static void main(String[] args) {
    LlogariBankare llogaria1 = new LlogariBankare("aaa", 1000); 
    llogaria1.Balanca();    
  }

}



class LlogariBankare {
  //variablat e instances
  private String id;
  private int nrLlogarise;
  private int vitiHapjes;
  private double balanca;
  static int nrTranasksioneve = 0;

  public LlogariBankare() {
    System.out.println("Ju keni harruar te vendosi id dhe nrLlogarise");

  }

  public LlogariBankare(String id, int nrLlogarise) {
    this.id = id;
    this.nrLlogarise = nrLlogarise;
    vitiHapjes = 0;
    balanca = 0; 
    Lexim(this.id, this.nrLlogarise); 
  }

  public double getBalanca() {
    return balanca;
  }

  public int getVitiHapjes() {
    return vitiHapjes;
  }

  private void Lexim(String s, int llog) {
    try {
      File file = new File("c:\\java\\balanca.txt");
      Scanner scanner = new Scanner(file);
      while (scanner.hasNextLine()) {
        if (scanner.next().equals(s) && scanner.nextInt() == llog) {
          vitiHapjes = scanner.nextInt();
          balanca = scanner.nextDouble();
        }
      }
    } catch (IOException e) {
      e.getMessage();
    }   
  }


  void Balanca() { 
    try{
      File file = new File("c:\\java\\test.txt");
      PrintWriter out = new PrintWriter(file);
      out.println(this.balanca);  
    } catch (IOException e) {
      e.getMessage();
    }   
    System.out.println(this.id + " , ju keni " + this.balanca + 
        " lek ne llogarine tuaj te krijuar ne vitin " + vitiHapjes + 
        " dhe keni kryer " + nrTranasksioneve + " transaksione gjithsej");
  }


  void Terheqe(double terheqe) {
    this.balanca -= terheqe;
    System.out.println("Ju sapo keni terhequr " + terheqe + " nga llogaria juaj");
    nrTranasksioneve++;
  }

  void Depozitim(double depozitim) {
    this.balanca += depozitim;
    System.out.println("Ju sapo keni depozituar " + depozitim + " nga llogaria juaj");
    nrTranasksioneve++;
  }


}

class Interesi extends LlogariBankare {
  int vitiTanishem = 2012;
  double interesi = 0;
  int diferencaViteve = vitiTanishem - getVitiHapjes();

  Interesi(String id, int nrLlogarise) {
    super(id,nrLlogarise); 
  }

  void gjejInteresisn() {
    interesi = getBalanca() + getBalanca() * diferencaViteve * 0.01;
  }

}

The file balanca has this line in it :
aaa 1000 1990 34000

In poor words this is some simple version of a bank.

You read the balance from a file, and
you use the Terheqe() and Depozitim() for – and + the balance.
You use Balance() to see how many $ you have. When I run it, this error show up:

Exception in thread "main" java.util.NoSuchElementException
at java.util.Scanner.throwFor(Scanner.java:907)
at java.util.Scanner.next(Scanner.java:1416)
at detyre_kursi.LlogariBankare.Lexim(Detyre_kursi.java:57)
at detyre_kursi.LlogariBankare.<init>(Detyre_kursi.java:40)
at detyre_kursi.Detyre_kursi.main(Detyre_kursi.java:11)

Java Result: 1

Answer 1

This line causing issue. scanner.nextInt() might not be an int and I feel it is not good to do two next() calls unless you have specific reason.

if(scanner.next().equals(s)&&scanner.nextInt()==llog){