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You might have to add the derbyclient.jar to the build, so it can be accessed at runtime.
to create a new database you need to tell derby so:
jdbc:derby://localhost:1527/dbname;create=true
Please also check out the Derby Documentation and Quick Start Guide:
http://db.apache.org/derby/quick_start.html[^]
Derby is well documented and works fine. Best choice for integrated databases.
Have fun.
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Hello Everyone
iam learning programming in java i started in GUI programming i need to know how to make programs executable i use eclipse i tried to export it as a .jar but it didnt work
pls help
thanks.
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OmarSH wrote: i tried to export it as a .jar but it didnt work You need to provide more details than that. Remember, we cannot see your screen or the commands you may have used to create the .jar file. Please explain what you did to create the jar, what output you got, and what happened when you tried to run it.
One of these days I'm going to think of a really clever signature.
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i didnt use any commands ,i export it as a .jar file using eclipse IDE
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Well you still have not explained what happens. Please show us exactly what commands you use to run it, and what results you see?
One of these days I'm going to think of a really clever signature.
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hi
i open eclipse IDE i select on the class(in project explorer) by right click in the mouse ,i pressed export as a jar(one time as a runnable jar file and other as jar file) then next select the export destination
the program made a jar file on desktop i click on it it is open like explorer )
by the way i am using linux mint
thanks
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You cannot run java programs by clicking them, you have to use the java command, e.g.
java -jar myjavaprogram.jar
One of these days I'm going to think of a really clever signature.
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Thank you it is really worked
but how to make it like a program (install ,desktop icon, etc)
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Java is not designed to operate that way by default. However, there are some converters that may help[^].
One of these days I'm going to think of a really clever signature.
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Does it run if you hit the green arrow at the top? If so, just right click your project and export it Export -> Java --> Runnable Jar
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it is run when i press the green button but when i export it ass jar it didnt run
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hi friends....m a beginner in java language..plzz help me any1 by writing a code to generate dis pattern:
*
******
**********
************
**************
************
**********
*******
*
plzz help!!
Siddhartha
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This question continues to be posted by students on this course. Try thinking about the problem and breaking it down into logical steps:
- Set some counters with start values
- Write some number of asterisks (maybe by using a loop)
- Increment the counter that specifies the number of asterisks
- Check whether the maximum limit has been reached, and repeat if not
- Start the second loop, same as above but decrementing until the minimum is reached
One of these days I'm going to think of a really clever signature.
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Thanks a lot....ur steps helped me a lot..i even tried out some other patterns n it worked!! thanks again
Siddhartha
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Hi there,
Welcome to the Java language. It's actually quite simple. Although there is no unique answer - there are similar ways to write a code for generating such a pattern.
Break down the problem into parts and from there you can move forward.
Live Support Software for Business
April
Comm100 - Leading Live Chat Software Provider
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Isn't that what I already suggested?
One of these days I'm going to think of a really clever signature.
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thanks..i finally managed to write the program code..after compiling it showed some error at first..but at the end i was able to get the proper output!!
Siddhartha
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Congratulations! Good job!
With Kind Regards,
April
Comm100 - Leading Live Chat Software Provider
modified 27-May-14 8:35am.
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I am trying to create a java program that inputs an infix expression, then gives the output in postfix and prefix. So far the code compiled without errors but the answers for the postfix and prefix are not coming out correctly. Also the outputs come out wrong when i put parenthesis. I think my problem is in the methods for the postfix and infix conversion. This is my code so far:
import java.io.*;
import java.util.*;
public class InToPreToPos{
private static Stack<Character> operatorStack = new Stack<Character> ();
private static Stack<Comparable> operandStack = new Stack<Comparable> ();
private static String toPostfix(String infix){
StringTokenizer s = new StringTokenizer(infix);
String symbol, postfix = "";
while (s.hasMoreTokens()){
symbol = s.nextToken();
if (Character.isDigit(symbol.charAt(0))){
postfix = postfix + " " + (Integer.parseInt(symbol));
}else if (symbol.equals("(")){
Character operator = new Character('(');
operatorStack.push(operator);
}else if (symbol.equals(")")){
while (operatorStack.peek().charValue() != '('){
postfix = postfix + " " + operatorStack.pop();
}
operatorStack.pop();
}else{
while (!operatorStack.empty() && !(operatorStack.peek()).equals("(") && prec(symbol.charAt(0)) <= prec(operatorStack.peek().charValue()))
postfix = postfix + " " + operatorStack.pop();
Character operator = new Character(symbol.charAt(0));
operatorStack.push(operator);
}
}
while (!operatorStack.empty())
postfix = postfix + " " + operatorStack.pop();
return postfix;
}
private static String toPrefix(String infix){
StringTokenizer pre = new StringTokenizer(infix);
String symbol1 , prefix= "";
while(pre.hasMoreTokens()){
symbol1 = pre.nextToken();
if(Character.isDigit(symbol1.charAt(0))){
prefix = prefix+ " " +(Integer.parseInt(symbol1));
}else if(symbol1.equals("(")){
Character operand = new Character('(');
operandStack.push(operand);
}else if(symbol1.equals(")")){
while (((Character)operandStack.peek()).charValue()!= '('){
prefix = prefix + " " + operandStack.pop();
}
operandStack.pop();
}else{
while(!operandStack.empty()&&!(operandStack.peek()).equals("(")
&& prec(symbol1.charAt(0))<= prec(((Character)operandStack.peek()).charValue()))
prefix = prefix + " "+ operandStack.pop();
Character operand = new Character(symbol1.charAt(0));
operandStack.push(operand);
}
}
while(!operandStack.empty())
prefix = prefix + " " +operandStack.pop();
return prefix;
}
private static int prec(char x){
if (x == '+' || x == '-'){
return 1;
}
else if (x=='^' && x == '*' || x == '/' || x == '%'){
return 2;
}
else{
return 0;
}
}
public static void main(String args[]) throws IOException{
BufferedReader keyboard = new BufferedReader (new InputStreamReader(System.in));
String infix;
System.out.print("Input a infix: ");
infix = keyboard.readLine();
System.out.println("Expression in postfix:" + toPostfix(infix));
System.out.println("Expression in prefix: " + toPrefix(infix));
}
}
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Sir, your problem is a lac of knowledge about debugging:
Debugging with Eclipse[^]
Debugging with Netbeans[^]
You will figure where your code goes wrong when you debug it step-by-step.
Also - far too much static functions. But that might be because of presenting it here.
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Hello...I'm writing a sudoku project, which can solve a sudoku table with backtracking algortihm...but when I test the value of "matrix" array by debugging I see that these are not correct....can any body help me?
This is an example of input file :
3 0 0 9 0 0 2 0 0
0 0 5 0 0 0 0 0 7
6 0 0 0 3 0 0 0 8
0 0 0 0 6 1 0 4 0
0 4 0 0 0 0 7 0 0
0 3 6 0 0 0 0 9 0
0 2 7 0 0 0 0 0 0
0 0 0 0 1 0 8 0 5
0 9 0 2 0 8 0 0 0
package filesudoku;
import java.io.*;
import java.util.*;
import java.lang.Exception;
public class Sudoku {
public static int[][] matrix;
public static int counter = 0;
public static String matrixView;
public static void main(String[] args) throws FileNotFoundException{
System.out.print("Please enter file name: ");
Scanner in = new Scanner(System.in);
String fileName = in.next();
matrixCreate(fileName);
}
public static void matrixCreate(String fileName) throws FileNotFoundException {
File getFile = new File(fileName);
Scanner scan = new Scanner(getFile);
matrixView = null;
while (scan.hasNextLine()){
matrixView = scan.nextLine();
counter++;
System.out.println(matrixView);
}
scan.close();
matrix = new int[counter] [matrixView.length()];
scan = new Scanner(getFile);
char getCol;
for (int rows = 0; rows < counter; rows++){
matrixView = scan.nextLine();
for (int cols = 0; cols < matrixView.length(); cols++){
getCol = matrixView.charAt(cols);
matrix[rows] [cols] = getCol;
}
}
}
}
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Member 8586072 wrote: but when I test the value of "matrix" array by debugging I see that these are not correct. You need to explain what values you are seeing and where, and why they are incorrect.
One of these days I'm going to think of a really clever signature.
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Yeah you're right...ok...as you see in the input file , the values in the first line ais like this : 3 0 0 9 0 0 2 0 0
it means that in array (matrix[][]) the values should be like this :
matrix[0][0]=3
matrix[0][1]=0
matrix[0][2]=0
matrix[0][3]=9
.
.
.
and so on...until matrix[8][8]=0...(as we have in input file)
but what I see is like this :
matrix[0][0]=51 !!!!!
matrix[0][1]=32...
matrix[0][2]=48...
and so on until the last one....and the interesting thing is that the size of the matrix that I defined in my code is matrix[9][9]...but when I debug the code it's like that :
matrix[9][17]!!!! I mean the last element of matrix is in matrix[8][16] with "48" for the value...
I hope that I've explained clearly...if it's not obvious tell me to explain more...
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Your counter is being increment by 1 too many because you increment it even when trying to read beyond the last line; you should only increment it when you get a complete line of values. You are setting the number of columns to the length of the final line read in, but this is wrong as there are more characters than actual digits in the line. And finally, you are setting the values in your matrix to each successive character in the input line, rather than tokenising the string into the successive digits and converting them to integers.
One of these days I'm going to think of a really clever signature.
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Wowww...Thank you Mr.Richard
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