Input from Command Line rather than from a text file

[thomas6]

Hi. I have the following code which takes input (a username and password) from a text file, reads it in and prints it out in a Binary Search Tree. I have to modify it so it doesn't read from a file, instead the usernames and passwords are enterered at the command line. Nothing I do seems to work. Any help would be appreciated. Thanks.

 import java.util.Scanner;
import java.io.*;

public class Run
 {

        public static void run()
        {
                BSTree input = new BSTree();        
                
                int lineno = 0;
                
                try {
        FileReader fr = new FileReader("file.txt");
        BufferedReader reader = new BufferedReader(fr);
        String line = reader.readLine();
        Scanner scan = null;
        while (line != null) {
        scan = new Scanner(line);
        String u = "";
        String p = "";
        u = scan.next();
        p = scan.next();
        
        if (lineno == 0)
        {
                input.username = u;
                input.password = p;
                lineno++;
        }
        
        else
        {
                input = addtoBSTree(u, p, input);
        }
        
        line = reader.readLine();
        
        }
                printBST(input);
                
        reader.close();
        
        }


        catch (FileNotFoundException e) {
                System.out.println("Could not find the file");
        }
        catch (IOException e) {
                System.out.println("Had a problem reading from file");
        }

        }
                
        
        
        public static void main(String args[])
    {
                run();

    }
        
        public static BSTree addtoBSTree(String u, String p, BSTree t) {

        if (t == null) return (new BSTree(u, p));
        if (sort (u, t.username)) return (new BSTree(t.username, t.password,
                        addtoBSTree(u, p, t.left), t.right));

        else return (new BSTree(t.username, t.password, t.left, addtoBSTree(u, p, 
                        t.right)));
        }

        public static boolean sort (String s1, String s2){
        if (s1.length() == 0) return true;
        if (s2.length() == 0) return false;
        if (s1.charAt(0) < s2.charAt(0)) return true;
        if (s1.charAt(0) == s2.charAt(0)) return
        (sort(s1.substring(1),s2.substring(1)));
        return false;
            }

        public static void printBST(BSTree t){
                if (t == null) return;
                else {printBST(t.left);
                System.out.println("Username: " + t.username);
                System.out.println("Password: " + t.password);
                System.out.println("");
                printBST(t.right);
                        }
        }


public class BSTree {

                      String username;
                String password;
                BSTree left;
                BSTree right;

               public BSTree (String u, String p, BSTree l, BSTree r) {
                        
                               username = u;
                        password = p;
                        left = l; 
                        right = r;

                }

                public BSTree (String u, String p) {

                        username = u;
                        password = p; 
                        left = null; 
                        right = null;

                }
                
                public BSTree () {

                    username = null;
                    password = null; 
                    left = null; 
                    right = null;

            }
                
                }

[ksemeks]

You can use

System.out.print("Input username: "); 
BufferedReader userInput = new BufferedReader(new InputStreamReader(System.in));
try
{
        String user = userInput.readLine();
}
catch (IOException e)
{
..
}

for the input from a console.
You should however delete the part of code which asks for a file input.

[thomas6]

Thanks ksemeks, I've added that and it appears to take in the username but it doesn't seem to add it to the binary search tree. Also, how would I go about entering a password as well? Thanks

EDIT, here is what I currently have;

import java.util.Scanner;
import java.io.*;

public class Run
 {

        public static void run()
        {
       
        	BSTree input = new BSTree();        
        	
        	System.out.print("Input username: "); 
        	BufferedReader userInput = new BufferedReader(new InputStreamReader(System.in));
        	try
        	{
        	        String user = userInput.readLine();
        	        String u = "";
        	        String p = "";
        	        input.username = u;
        	        input.password = p;
                    input = addtoBSTree(u, p, input);
                    printBST(input);


        	}
        	catch (IOException e)
        	{
        		System.out.println("IO error trying to read your name!");
                System.exit(1);
        	}
        	
        
        }
                
        
        
        public static void main(String args[]) throws Exception 
    {
                run();

    }
        
        public static BSTree addtoBSTree(String u, String p, BSTree t) {

        if (t == null) return (new BSTree(u, p));
        if (sort (u, t.username)) return (new BSTree(t.username, t.password,
                        addtoBSTree(u, p, t.left), t.right));

        else return (new BSTree(t.username, t.password, t.left, addtoBSTree(u, p, 
                        t.right)));
        }

        public static boolean sort (String s1, String s2){
        if (s1.length() == 0) return true;
        if (s2.length() == 0) return false;
        if (s1.charAt(0) < s2.charAt(0)) return true;
        if (s1.charAt(0) == s2.charAt(0)) return
        (sort(s1.substring(1),s2.substring(1)));
        return false;
            }

        public static void printBST(BSTree t){
                if (t == null) return;
                else {printBST(t.left);
                System.out.println("Username: " + t.username);
                System.out.println("Password: " + t.password);
                System.out.println("");
                printBST(t.right);
                        }
        }
 }

[ksemeks]

thomas6, well, at least learn some fundamental java programming.

So, replace this lines

        FileReader fr = new FileReader("file.txt");
        BufferedReader reader = new BufferedReader(fr);
        String line = reader.readLine();
        Scanner scan = null;
        while (line != null) {
        scan = new Scanner(line);
        String u = "";
        String p = "";
        u = scan.next();
        p = scan.next();

with this

        System.out.print("Input username: "); 
        BufferedReader userInput = new BufferedReader(new InputStreamReader(System.in));
        	try
        	{
        		String u = userInput.readLine();
        	}
        	catch (IOException e)
        	{
        		e.printStackTrace();
        	}
        	
        System.out.print("Input password: "); 
        BufferedReader userInput = new BufferedReader(new InputStreamReader(System.in));
        	try
        	{
        		String p = userInput.readLine();
        	}
        	catch (IOException e)
        	{
        		e.printStackTrace();
        	}

And put away the reader and line objects, get rid of yours 2 exceptions(FileNotFound and IOException), and you can put away the java.util.Scanner since you won't be needing it.