Why won't this see the 'string'.. basic java help.
I am not trying to get someone to do my homework, yes this is indeed homework I just want some help.
errors
bah.java:81: variable anEmail might not have been initialized
if (anEmail==email)// get ignorecase to work
^
bah.java:86: variable anEmail might not have been initialized
email[nEmails++] = anEmail;
^
2 errors
//
import java.io.*;
import java.util.*;
import java.text.*;
import java.lang.*;
publicclass bah
{
publicstaticvoid main(String[] args)throws Exception
{
//initialize keyboard reader
BufferedReader cin;
cin =new BufferedReader(new InputStreamReader(System.in));
//initialize strings
String inputFilename;
String outputFilename;
String defaultFilename ="file.txt";
//initialize array
String[] email =new String[1000];
//Collect inputfile name or default
System.out.println("What is file name to be read? (enter for default)");
inputFilename = cin.readLine();
if (inputFilename.length() == 0)
inputFilename = defaultFilename;
//Collect outputfile name or default
System.out.println("What is file name to be created? (enter for default)");
outputFilename = cin.readLine();
if (outputFilename.length() == 0)
outputFilename = defaultFilename;
// open a file for input
BufferedReader fin;
fin =new BufferedReader(new FileReader(inputFilename));
String lineFromFile = fin.readLine();
int i;//loop counter
for (i = 0; i < lineFromFile.length(); i++) ;
int s = i - 1;
int e = i + 1;
boolean hasDot =false;
Find:
if (lineFromFile.charAt(i) =='@')
{
//find start
if (s < 0)break Find;//following breaks have the "Find" to break from~~~~~~~~~~~~~~~~~~~~~~~
boolean isvalid =false;
if (lineFromFile.charAt(s) >='A' && lineFromFile.charAt(s) <='Z') isvalid =true;
if (lineFromFile.charAt(s) >='a' && lineFromFile.charAt(s) <='z') isvalid =true;
if (lineFromFile.charAt(s) =='.') isvalid =true;
if (lineFromFile.charAt(s) >='-') isvalid =true;
if (isvalid) s--;
elsebreak Find;
//find end
if (e == lineFromFile.length())break Find;//changed from
boolean valid =false;
if (lineFromFile.charAt(e) >='A' && lineFromFile.charAt(e) <='Z') valid =true;
if (lineFromFile.charAt(e) >='a' && lineFromFile.charAt(e) <='z') valid =true;
if (lineFromFile.charAt(e) =='.') valid =true;
if (lineFromFile.charAt(e) >='-') valid =true;
if (valid) e++;
if (lineFromFile.charAt(e) =='.') hasDot =true;
elsebreak Find;
}
//print to file
int nEmails=0;//number of emails
String anEmail;// a email
if (s < i && i < e && hasDot)
anEmail = lineFromFile.substring(s, e + 1);
boolean found =false;// check for matching e-mails
for (i = 0; i < nEmails; i++)
if (anEmail==email[i])// get ignorecase to work
found =true;
if (!found)
{
if (nEmails < email.length)
email[nEmails++] = anEmail;
}
//testing defaults disregard to be formatted later
System.out.println(inputFilename);
System.out.println(outputFilename);
System.out.println(nEmails);
}// main
}// public class
Message was edited by:
Scustoms
[7032 byte] By [
Scustomsa] at [2007-11-27 5:10:55]
String anEmail = lineFromFile.substring(s, e + 1);This line is not in your code. Make sure the file you are working on is the same as the file you are trying to compile.Changed your error messages on me I see.Message was edited by: flounder
Couple of changes. I've prefaced my comments with a //!!:
//!! add the = "" so that the variable is initialized.
String anEmail = "";// a email
if (s < i && i < e && hasDot)
//!! since this is in an if statement, it may not be true, and the line below
//!! may never be called to
//!! initialize anEmail. Thus you need the anEmail = "" above.
anEmail = lineFromFile.substring(s, e + 1);
boolean found = false; // check for matching e-mails
for (i = 0; i < nEmails; i++)
//!! change this: if (anEmail == email[i]) to the format below.
//!! == doesn't work for strings or objects, only primatives.
if (anEmail.equalsIgnoreCase(email[i]))
{
found = true;
}
Ok so i don't want to create a new thread.. but once i compile the following code i get the following error. One I haven't seen before.
!!Code in following post!! Won't let me add in a 'edit'!!!
Exception in thread "main" java.lang.StringIndexOutOfBoundsException: String ind
ex out of range: 0
at java.lang.String.charAt(String.java:687)
at bah.main(bah.java:49)
Message was edited by:
Scustoms
//
import java.io.*;
import java.util.*;
import java.text.*;
import java.lang.*;
public class bah
{
public static void main(String[] args) throws Exception
{
//initialize keyboard reader
BufferedReader cin;
cin = new BufferedReader(new InputStreamReader(System.in));
//initialize strings
String inputFilename;
String outputFilename;
String defaultFilename = "file.txt";
//initialize array
String[] email = new String[1000];
//Collect inputfile name or default
System.out.println("What is file name to be read? (enter for default)");
inputFilename = cin.readLine();
if (inputFilename.length() == 0)
inputFilename = defaultFilename;
//Collect outputfile name or default
System.out.println("What is file name to be created? (enter for default)");
outputFilename = cin.readLine();
if (outputFilename.length() == 0)
outputFilename = defaultFilename;
// open a file for input
BufferedReader fin;
fin = new BufferedReader(new FileReader(inputFilename));
String lineFromFile = fin.readLine();
int i; //loop counter
for (i = 0; i < lineFromFile.length(); i++) ;
int s = i - 1;
int e = i + 1;
boolean hasDot = false;
Find:
if (lineFromFile.charAt(i) == '@')
{
//find start
if (s < 0) break Find; //following breaks have the "Find" to break from~~~~~~~~~~~~~~~~~~~~~~~
boolean isvalid = false;
if (lineFromFile.charAt(s) >= 'A' && lineFromFile.charAt(s) <= 'Z') isvalid = true;
if (lineFromFile.charAt(s) >= 'a' && lineFromFile.charAt(s) <= 'z') isvalid = true;
if (lineFromFile.charAt(s) == '.') isvalid = true;
if (lineFromFile.charAt(s) >= '-') isvalid = true;
if (isvalid) s--;
else break Find;
//find end
if (e == lineFromFile.length()) break Find;//changed from
boolean valid = false;
if (lineFromFile.charAt(e) >= 'A' && lineFromFile.charAt(e) <= 'Z') valid = true;
if (lineFromFile.charAt(e) >= 'a' && lineFromFile.charAt(e) <= 'z') valid = true;
if (lineFromFile.charAt(e) == '.') valid = true;
if (lineFromFile.charAt(e) >= '-') valid = true;
if (valid) e++;
if (lineFromFile.charAt(e) == '.') hasDot = true;
else break Find;
}
//print to file
int nEmails=0;//number of emails
String anEmail = "";// a email
if (s < i && i < e && hasDot)
anEmail = lineFromFile.substring(s, e + 1);
boolean found = false; // check for matching e-mails
for (i = 0; i < nEmails; i++)
if (anEmail.equalsIgnoreCase(email[i]))// get ignorecase to work
{
found = true;
}
if (!found)
{
if (nEmails < email.length)
email[nEmails++] = anEmail;
}
//testing defaults disregard to be formatted later
System.out.println(inputFilename);
System.out.println(outputFilename);
System.out.println(nEmails);
} // main
}// public class
> Ok so i don't want to create a new thread.. but once> i compile the following code i get the following> error. One I haven't seen before.> did my previous recommendations help? If so, please say so. If not, please say why not.
Oh yeah sorry i edited my post when i said thanks! I can't believe how fast you replied and I also hit my head on the wall a few time for not remembering the ""; to initialize the string. It complied but now i get the above error? Appreciate it for sure.
That's because a string "" has no chars so there isn't a char at position 0 or any other position. Before you go using chatAt perhaps you should check the length of the String is > 0.
your for loop is broken.
for (i = 0; i < lineFromFile.length(); i++) ;
for loops don't have semicolons after them, they have curly braces that enclose the code that is to be looped. the semicolon at the end makes it loop an empty statement.
Also, please get rid of all the "breaks" as they are surely a sign of poorly written code (exceptions exist such as switch / case statements).
good luck
They are using break for a specific reason, to break back to Find (forget the name for it).
> They are using break for a specific reason, to break> back to Find (forget the name for it).Flounder, I agree, but would you implement it this way?
Hmm we were instructed to used the break statement but in the following format, the 'find' was something i worked in to umm cover myself somewhere else where I couldn't get it to work. The code i was trying to get to work with all the above implementation is this, but it doesn't want to break and returns these errors.
bah2.java:52: break outside switch or loop
if (s < 0) break; //following breaks have the "
Find" to break from~~~~~~~~~~~~~~~~~~~~~~~
^
bah2.java:59: break outside switch or loop
else break;
^
bah2.java:62: break outside switch or loop
if (e == lineFromFile.length()) break;//chang
ed from
^
bah2.java:70: break outside switch or loop
else break;
//
import java.io.*;
import java.util.*;
import java.text.*;
import java.lang.*;
public class bah2
{
public static void main(String[] args) throws Exception
{
//initialize keyboard reader
BufferedReader cin;
cin = new BufferedReader(new InputStreamReader(System.in));
//initialize strings
String inputFilename;
String outputFilename;
String defaultFilename = "file.txt";
//initialize array
String[] email = new String[1000];
//Collect inputfile name or default
System.out.println("What is file name to be read? (enter for default)");
inputFilename = cin.readLine();
if (inputFilename.length() == 0)
inputFilename = defaultFilename;
//Collect outputfile name or default
System.out.println("What is file name to be created? (enter for default)");
outputFilename = cin.readLine();
if (outputFilename.length() == 0)
outputFilename = defaultFilename;
// open a file for input
BufferedReader fin;
fin = new BufferedReader(new FileReader(inputFilename));
String lineFromFile = fin.readLine();
int i; //loop counter
int s = i - 1;
int e = i + 1;
boolean hasDot = false;
for (i = 0; i < lineFromFile.length(); i++) ;
{
if (lineFromFile.charAt(i) == '@')
{
//find start
if (s < 0) break; //following breaks have the "Find" to break from~~~~~~~~~~~~~~~~~~~~~~~
boolean isvalid = false;
if (lineFromFile.charAt(s) >= 'A' && lineFromFile.charAt(s) <= 'Z') isvalid = true;
if (lineFromFile.charAt(s) >= 'a' && lineFromFile.charAt(s) <= 'z') isvalid = true;
if (lineFromFile.charAt(s) == '.') isvalid = true;
if (lineFromFile.charAt(s) >= '-') isvalid = true;
if (isvalid) s--;
else break;
//find end
if (e == lineFromFile.length()) break;//changed from
boolean valid = false;
if (lineFromFile.charAt(e) >= 'A' && lineFromFile.charAt(e) <= 'Z') valid = true;
if (lineFromFile.charAt(e) >= 'a' && lineFromFile.charAt(e) <= 'z') valid = true;
if (lineFromFile.charAt(e) == '.') valid = true;
if (lineFromFile.charAt(e) >= '-') valid = true;
if (valid) e++;
if (lineFromFile.charAt(e) == '.') hasDot = true;
else break;
}
}
//print to file
int nEmails=0;//number of emails
String anEmail = "";// a email
if (s < i && i < e && hasDot)
anEmail = lineFromFile.substring(s, e + 1);
boolean found = false; // check for matching e-mails
for (i = 0; i < nEmails; i++)
if (anEmail.equalsIgnoreCase(email[i]))// get ignorecase to work
{
found = true;
}
if (!found)
{
if (nEmails < email.length)
email[nEmails++] = anEmail;
}
//testing defaults disregard to be formatted later
System.out.println(inputFilename);
System.out.println(outputFilename);
System.out.println(nEmails);
} // main
}// public class
Would that be more appropriate if it worked?
> Flounder, I agree, but would you implement it this way?
I haven't looked closely at the code to see what they are trying to achieve. So cannot comment on if this is good or bad in this situation. Just clarifying theat using breaks that are not in a switch statement can be good programming IF the situation needs it.
You haven't fixed the problem mentioned in reply #8.
Oops thats fustrating lol thought i didn't ! My bad. Ok so anyhow here is how i stand and now its giving me this error.
bah2.java:44: variable i might not have been initialized
int s = i - 1;
^
1 error
//
import java.io.*;
import java.util.*;
import java.text.*;
import java.lang.*;
public class bah2
{
public static void main(String[] args) throws Exception
{
//initialize keyboard reader
BufferedReader cin;
cin = new BufferedReader(new InputStreamReader(System.in));
//initialize strings
String inputFilename;
String outputFilename;
String defaultFilename = "file.txt";
//initialize array
String[] email = new String[1000];
//Collect inputfile name or default
System.out.println("What is file name to be read? (enter for default)");
inputFilename = cin.readLine();
if (inputFilename.length() == 0)
inputFilename = defaultFilename;
//Collect outputfile name or default
System.out.println("What is file name to be created? (enter for default)");
outputFilename = cin.readLine();
if (outputFilename.length() == 0)
outputFilename = defaultFilename;
// open a file for input
BufferedReader fin;
fin = new BufferedReader(new FileReader(inputFilename));
String lineFromFile = fin.readLine();
int i; //loop counter
int s = i - 1;
int e = i + 1;
boolean hasDot = false;
for (i = 0; i < lineFromFile.length(); i++)
{
if (lineFromFile.charAt(i) == '@')
{
//find start
if (s < 0) break; //following breaks have the "Find" to break from~~~~~~~~~~~~~~~~~~~~~~~
boolean isvalid = false;
if (lineFromFile.charAt(s) >= 'A' && lineFromFile.charAt(s) <= 'Z') isvalid = true;
if (lineFromFile.charAt(s) >= 'a' && lineFromFile.charAt(s) <= 'z') isvalid = true;
if (lineFromFile.charAt(s) == '.') isvalid = true;
if (lineFromFile.charAt(s) >= '-') isvalid = true;
if (isvalid) s--;
else break;
//find end
if (e == lineFromFile.length()) break;//changed from
boolean valid = false;
if (lineFromFile.charAt(e) >= 'A' && lineFromFile.charAt(e) <= 'Z') valid = true;
if (lineFromFile.charAt(e) >= 'a' && lineFromFile.charAt(e) <= 'z') valid = true;
if (lineFromFile.charAt(e) == '.') valid = true;
if (lineFromFile.charAt(e) >= '-') valid = true;
if (valid) e++;
if (lineFromFile.charAt(e) == '.') hasDot = true;
else break;
}
}
//print to file
int nEmails=0;//number of emails
String anEmail = "";// a email
if (s < i && i < e && hasDot)
anEmail = lineFromFile.substring(s, e + 1);
boolean found = false; // check for matching e-mails
for (i = 0; i < nEmails; i++)
if (anEmail.equalsIgnoreCase(email[i]))// get ignorecase to work
{
found = true;
}
if (!found)
{
if (nEmails < email.length)
email[nEmails++] = anEmail;
}
//testing defaults disregard to be formatted later
System.out.println(inputFilename);
System.out.println(outputFilename);
System.out.println(nEmails);
} // main
}// public class
Look at this code:
int i; //loop counter
int s = i - 1;
int e = i + 1;
What does "i" equal? well, possibly 0 if compiler initializes it to 0, but who really knows since i has not been given any value.
Another overgeneralization here: I try not to play with my loop indices before a for loop. I try to create an int variable in the for statement itself (for (int i = 0....) and not set it to anything inside the loop or outside (well I can't if created this way since it is local only to the loop). Of course there are exceptions, but it may help prevent errors like this one.
Good luck.
int i;int s = i - 1; Error messages are there for a reason. What value do you thing s will have?
anyways, flounder is a lot smarter at this than i am. since he's involved, i'm bowing out. again, good luck.
firstly you have to initialize variable or you have to write else part and assign any value for anEmail variableString anEmail="";orif (s < i && i < e && hasDot)anEmail = lineFromFile.substring(s, e +
Thanks for that Suraweera but that problem was fixed over an hour ago.
Pete1234
No need to bow out input is helpful, either way thanks mucho I appreciate it!
Flounder
I initialized i to 0 and i get some input I am going to go offline for a bit and beat myhead against the wall, i don't want to lean on anyone to much. I will be working on this tomorrow if i can't get it squared away.
All
I appreciate it, awesome forum. Thanks!
