John Saito

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since Nov 08, 2005

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Recent posts by John Saito

reading input from a file into a array

this is the code i have to read from the file:

I know its not complete but im clueless where to go from here.

this is the code for saving the list to a .txt.:

this outputs "OneWayNoRepeatsList@757aef" in the text file. how do i get the records that are stored in the array to save into the file.

18 years ago

Beginning Java

reading input from a file into a array

the original program was a database program which keeps track of customers. Right now customer names is the only required field. the program can add, delete, search and list all records (names). There are 2 other classes that go along with this program. (sortString, OneWayNoRepeatList) all of this works just fine, what I am trying to add to the program the ability to save/read all records to a .txt file. I created 2 methods, CustomerList and saveRecords. customerList is where i want the program to read all records into the program (array) so that if a user chooses option 1, all records will be listed, including what is in the .txt file. Then if the user chooses to save, the entire list is saved to the .txt file. I dont need the option 5, which was to load the file.

18 years ago

Beginning Java

reading input from a file into a array

thanks for the help so far. what i am trying to do is, to get this program to read in any names stored in a txt file (Customer List.txt) and insert them into the array. this program will allow users to add to a list, search the list for a name and delete from the list. I want to add to it buy being able to save and read from a file. It would be better if the program could read the file automatically when it is first ran. hope this clears up what i am trying to do.

18 years ago

Beginning Java

reading input from a file into a array

hello, i am trying to read a list of names from a .txt file into a array when the program starts. I am completly stuck on this. this is the code is have so far but no matter what i try its not working. please help.

import java.util.*;
import java.io.*;
public class Project2
{
private static int MAX_LIST_LENGTH = 10;
private static OneWayNoRepeatsList toDoList = new OneWayNoRepeatsList(MAX_LIST_LENGTH); // creating toDoList
private static void DisplayCustomerList()
{
Scanner keyboard = new Scanner(System.in); // uses Scanner for reading
System.out.println("");
System.out.println("****** CUSTOMER DATABASE: VIEW LIST ******");
System.out.println("");
if (toDoList.empty())
{
System.out.println("The customer list is currently empty.");
}
else
{
System.out.println("Customers:"); // writing out entire toDoList
int position = toDoList.START_POSITION;
String next = toDoList.getEntryAt(position);
while (next != null) // null indicates end of list
{
System.out.println(position + ".\t" + next);
position++;
next = toDoList.getEntryAt(position);
}
System.out.println("Total customers:" + (position-1));
}
System.out.println("");
System.out.println("Press Enter to return to the menu");
String next = keyboard.nextLine();
}
private static void AddCustomersToList()
{
Scanner keyboard = new Scanner(System.in); // uses Scanner for reading
System.out.println("");
System.out.println("****** CUSTOMER DATABASE: ADD CUSTOMERS ******");
System.out.println("");
if (toDoList.full())
{
System.out.println("List is currently full");
}
else
{
System.out.println("When prompted, enter customer names to be added to the list");
System.out.println("");
boolean more = true;
while ( more && (! toDoList.full( )))
{
System.out.println("Customer Name? ");
String next = "";
while (next.length() == 0)
{
next = keyboard.nextLine( );
}
if (toDoList.onList(next))
{
System.out.println(next + " is already in the customer list.");
}
else
{
toDoList.addItem(next);
System.out.println("Successfully added " + next + " to the customer list.");
}
if (toDoList.full( ))
{
System.out.println("List is now full. Press Enter to return to the menu.");
next = keyboard.nextLine();
}
else
{
System.out.println("Add more customers? (\"yes\" or \"no\") ");
String ans = keyboard.nextLine();
if (ans.trim().equalsIgnoreCase("no"))
more = false;
}
}
}
}
private static int FindCustomerNameIndex(String strName)
{
int iIndex = -1;
int position = toDoList.START_POSITION;
String next = toDoList.getEntryAt(position);
boolean bFoundName = false;
boolean bEndOfList = false;
while ((!bFoundName) && (!bEndOfList)) // null indicates end of list
{
if ((next != null) && (next.equalsIgnoreCase(strName)))
{
bFoundName = true;
iIndex = position;
}
if (toDoList.atLastEntry(position))
{
bEndOfList = true;
}
else
{
position++;
next = toDoList.getEntryAt(position);
}
}
return iIndex;
}
private static void DeleteCustomersFromList()
{
Scanner keyboard = new Scanner(System.in); // uses Scanner for reading
System.out.println("");
System.out.println("****** CUSTOMER DATABASE: DELETE CUSTOMERS ******");
System.out.println("");
if (toDoList.empty())
{
System.out.println("List is currently empty");
}
else
{
System.out.println("When prompted, enter customer names to be deleted from the list");
System.out.println("");
boolean more = true;
while (more && (!toDoList.empty()))
{
System.out.println("Customer Name? ");
String next = keyboard.nextLine();
int iCustomerPosition = FindCustomerNameIndex(next);
if (iCustomerPosition == -1)
{
System.out.println("Unable to find " + next + " in the list.");
}
else
{
toDoList.deleteItem(iCustomerPosition);
System.out.println("Successfully deleted " + next + " from the list.");
}
if (toDoList.empty( ))
{
System.out.println("List is empty.");
}
else
{
System.out.println("Delete more customers? (\"yes\" or \"no\") ");
String ans = keyboard.nextLine();
if (ans.trim().equalsIgnoreCase("no"))
more = false;
}
}
}
}
private static void FindCustomersInList()
{
Scanner keyboard = new Scanner(System.in); // uses Scanner for reading
System.out.println("");
System.out.println("****** CUSTOMER DATABASE: FIND CUSTOMERS ******");
System.out.println("");
if (toDoList.empty())
{
System.out.println("List is currently empty");
}
else
{
System.out.println("When prompted, enter customer names to be searched for in the list");
boolean more = true;
while (more)
{
System.out.println("Customer Name? ");
String next = keyboard.nextLine();
int iCustomerIndex = FindCustomerNameIndex(next);
if (iCustomerIndex == -1)
{
System.out.println("Unable to find " + next + " in the list.");
}
else
{
System.out.println(next + " is in the list at position: " + iCustomerIndex);
}
System.out.println("Search for more customers? (\"yes\" or \"no\") ");
String ans = keyboard.nextLine( );
if (ans.trim().equalsIgnoreCase("no"))
more = false;
}
}
}
private static void saveRecords()
{
PrintWriter outputStream = null;
try
{
outputStream = new PrintWriter(new FileOutputStream("Customer List.txt"));
}
catch(FileNotFoundException e)
{
System.out.println("Error opening file Customer List.txt");
System.exit(0);
}
{
outputStream.println(next[0]);
}
outputStream.close();
System.out.println("Those customers were written to Customer List.txt");
}
private static void customerList()
{
try
{
BufferedReader inputStream = new BufferedReader(new FileReader("List.txt"));
String line = null;
line = inputStream.readLine();
System.out.println("First Name is: ");
System.out.println(line);
inputStream.close();
}
catch(FileNotFoundException e)
{
System.out.println("File not Found");
}
catch(IOException e)
{
System.out.println("Error reading from file ");
}
}
public static void main(String[] args)
{
Scanner keyboard = new Scanner(System.in); // uses Scanner for reading
// loop until the user says to exit
boolean bExit = false;
while (!bExit)
{
System.out.println("****** CUSTOMER DATABASE: MAIN MENU ******");
System.out.println("");
System.out.println("What would you like to do?");
System.out.println("1. View customer list");
System.out.println("2. Add customer(s) to list");
System.out.println("3. Delete customer(s) from list");
System.out.println("4. Search for customer(s)");
System.out.println("5. load customer(s) file");
System.out.println("6. Save customer(s) to file");
System.out.println("7. Exit");
//get choice from user
int menuChoice = keyboard.nextInt( );
switch (menuChoice)
{
case 1:
DisplayCustomerList();
break;
case 2:
AddCustomersToList();
break;
case 3:
DeleteCustomersFromList();
break;
case 4:
FindCustomersInList();
break;
case 5:
customerList();
break;
case 6:
saveRecords();
break;
case 7:
System.out.println("Thank you for using SwainCo Software. Goodbye.");
bExit = true;
break;
default:
System.out.println("Invalid entry");
break;
}
}
}
}

any help is greatly appriciated.

18 years ago

Beginning Java

loop problem

hello, i was wondering if someone could tell me what im doing wrong. i need to add a loop to my program, simply asking the user if her or she wants to continue. no matter what i try i get nothing but errors. i am trying to use "while" in this. here part of the program.
System.out.println("enter a number to convert");
iInput = Integer.parseInt(keyboard.readLine());

System.out.println("Enter units (M or K)");
cUnit = (char) System.in.read();
double dResult;
String strResult;
while ((cOption == 'Y') || (cOption == 'y')){

if ((cUnit == 'm') || (cUnit == 'M'))
{ //do math to determine Miles.
dResult = KMToMiles(iInput);
strResult = "Miles converted is ";
System.out.println(strResult + dResult);
}
else if ((cUnit == 'k') || (cUnit == 'K'))
{ //do math to determine Kilometers.
dResult = MilesToKM(iInput);
strResult = "Kilometers converted is ";
System.out.println(strResult + dResult);
}

please help.

John

18 years ago

Beginning Java