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farne

Posts: 3732

Posted: Wed, 25th May 2011 13:40 Post subject: Java: Swing banking account

Heya.

I have taken on a project for myself and I've made a banking account in swing which lets me withdraw a certain amount of money ( without going below 0 ) and deposit whichever amount I see fit.

However, I want to improve my program a little bit, I have made a function that allows me to see the current amount of money on the bank account, and now I want the program to write an external file with a value ( the amount of money on the account ) that I will load whenever I want to launch the program.

Is there an easy way to do this?

Spoiler:

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garus
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Posts: 34200

Posted: Wed, 25th May 2011 13:55 Post subject:	Quick Quote Quote

snip Last edited by garus on Tue, 27th Aug 2024 21:54; edited 1 time in total

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farne

Posts: 3732

Posted: Wed, 25th May 2011 14:17 Post subject:	Quick Quote Quote

Thanks a lot for the fast response. Jjust trying to piece it all together now, seem to have gotten stuck with just one cimpilation error though, any pointers as to how to assemble it all? Did import java.io, but it's still a bit jerky for me.

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garus
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Posts: 34200

Posted: Wed, 25th May 2011 14:19 Post subject:	Quick Quote Quote

snip Last edited by garus on Tue, 27th Aug 2024 21:54; edited 1 time in total

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farne

Posts: 3732

Posted: Wed, 25th May 2011 14:53 Post subject:	Quick Quote Quote

And the output imports ofc If anyone knows how to assemble it all, please, dont be shy, itching my head furiously right now.

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farne

Posts: 3732

Posted: Fri, 27th May 2011 02:12 Post subject:

I got most of it working right now, I can write a textfile by executing the program and all but I cant seem to find a way to grab the value of "saldo" and put it into the textfile, because to get it all to work I have to throw away the exceptions :s

Code:

import javax.swing.*;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.File;
import java.io.DataInputStream;
import java.io.DataOutputStream;
public class BRKBank
{
public static void main(String args[]){
boolean fortsätt = true;
double pengar = 1;
double saldo = 11000;
String in;
int val;

do
{
in = JOptionPane.showInputDialog("Välkommen till BRKBank \n" +
"1. Uttag\n" +
"2. Insättning\n" +
"3. Saldo\n" +
"4. Avsluta\n" +
"Vad vill du göra?");
val = Integer.parseInt(in);

switch(val)
{
case 1:
in = JOptionPane.showInputDialog("Hur mycket pengar vill du ta ut?");
pengar = Double.parseDouble(in);
FileInputStream fis = new FileInputStream("saldo.txt");
            DataInputStream dis = new DataInputStream(fis);

            saldo = dis.readInt();
dis.close();
if (saldo <= pengar ) {
      JOptionPane.showMessageDialog(null, "Du får inte ta ut så här mycket pengar");
         break;}
saldo = saldo-pengar;

break;
case 2:
in = JOptionPane.showInputDialog("Hur mycket pengar vill du sätta in?");
pengar = Double.parseDouble(in);
saldo = saldo+pengar;
break;
case 3:
JOptionPane.showMessageDialog(null, "Du har nu: " + saldo + " kr på ditt konto");
break;
case 4:
fortsätt = false;
break;
default:
JOptionPane.showMessageDialog(null, "Försök igen.");
}
if(val == 1 || val == 2 )
JOptionPane.showMessageDialog(null, "Du har nu: " + saldo + " kr på ditt konto");

}while(fortsätt);
FileOutputStream fos = new FileOutputStream("saldo.txt");
DataOutputStream dos = new DataOutputStream(fos);
   dos.writeDouble(saldo);
dos.close();

System.exit(0);
}
}

Halp, pretty plx.

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farne

Posts: 3732

Posted: Sun, 29th May 2011 18:26 Post subject:	Quick Quote Quote

Bufferedreader/writer is apparently very much needed for this kind of program, since the File***put reader can only apparently type down bytes.

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farne

Posts: 3732

Posted: Mon, 30th May 2011 13:24 Post subject:

Code:

import javax.swing.*;
import java.io.*;
public class BRKBank
{
public static void main(String args[]) throws java.io.IOException
{
{

}
boolean fortsätt = true;
double pengar = 1;
double saldo = 11000;
String in;
String saldoString;
int val;
saldoString = Double.toString(saldo);

do
{
in = JOptionPane.showInputDialog("Välkommen till BRKBank \n" +
"1. Uttag\n" +
"2. Insättning\n" +
"3. Saldo\n" +
"4. Avsluta\n" +
"Vad vill du göra?");
val = Integer.parseInt(in);

switch(val)
{
case 1:
in = JOptionPane.showInputDialog("Hur mycket pengar vill du ta ut?");
pengar = Double.parseDouble(in);
try {
      File file = new File("saldo.txt");
      FileReader fr = new FileReader(file);
      BufferedReader br = new BufferedReader(fr);
      while(( saldoString = br.readLine()) != null)
      {

      saldo = String.parseDouble(in);
      }
      } catch(IOException e) {
System.out.println("bad !");

}

if (saldo <= pengar ) {
      JOptionPane.showMessageDialog(null, "Du får inte ta ut så här mycket pengar");
         break;}
saldo = saldo - pengar;

break;
case 2:
in = JOptionPane.showInputDialog("Hur mycket pengar vill du sätta in?");
pengar = Double.parseDouble(in);
saldo = saldo + pengar;
break;
case 3:
JOptionPane.showMessageDialog(null, "Du har nu: " + saldo + " kr på ditt konto");
break;
case 4:
fortsätt = false;
break;
default:
JOptionPane.showMessageDialog(null, "Försök igen.");
}
if(val == 1 || val == 2 )
JOptionPane.showMessageDialog(null, "Du har nu: " + saldo + " kr på ditt konto");

}while(fortsätt);
saldoString = Double.toString(saldo);

File file =new File("saldo.txt");
if(!file.exists()){
   file.createNewFile();
}
FileWriter fw = new FileWriter(file.getName());
BufferedWriter bw = new BufferedWriter(fw);
bw.write(saldoString);
bw.close();
System.exit(0);
}
}

I have managed to make the program write out the exact amount of money that was in the last execution of the program, but I am unable to make the program read the .txt in a proper fashion, hoping that someone can help me with it, I refuse to give up!

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