December 2003 - openSUSE Programming - openSUSE Mailing Lists

C Programming in Linux
by KPP52＠aol.com 16 Dec '03

16 Dec '03

I have Personal 9.0 I wrote the basic C program first.c then I did: gcc -o first first.c then I tried to run it by typing: first and it gives me a message: bash first no such command. so I tried: gcc first.c there was an a.out file in the directory then I typed: a.out and it gives me the same error message. Is there something I'm missing with the C compiler here? I'm new to SuSE and new to linux in general. I have done some C programming in Unix and this is confusing me tremendously. Any help would be greatly appreciated.

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Singelton pattern
by Prabu Subroto 16 Dec '03

16 Dec '03

Dear my friends... I tried this singelton pattern. But I got this error message: === patrixlinux@patrix:~/arsip/My/coba-2x/1> javac Connector.java Connector.java:2: cannot resolve symbol symbol : class Connection location: class Connector private static Connection conn; ^ Connector.java:18: cannot resolve symbol symbol : class Connection location: class Connector public static Connection getConnection() { ^ Connector.java:7: cannot resolve symbol symbol : variable DriverManager location: class Connector conn = DriverManager.getConnection("jdbc:mysql://localhost/amt?user=root&password=pandawa5"); ^ Connector.java:12: cannot resolve symbol symbol : class SQLException location: class Connector } catch (SQLException sqle) { ^ Connector.java:31: cannot resolve symbol symbol : class SQLException location: class Connector } catch (SQLException sqle) { ^ Connector.java:41: cannot resolve symbol symbol : class PreparedStatement location: class Menu PreparedStatement ps = null; ^ Connector.java:44: cannot resolve symbol symbol : class Connection location: class Menu Connection con = Connector.getConnection(); ^ Connector.java:47: cannot resolve symbol symbol : class SQLException location: class Menu } catch (SQLException sqle) { ^ Connector.java:51: cannot resolve symbol symbol : class SQLException location: class Menu } catch (SQLException sqle) { ^ 9 errors patrixlinux@patrix:~/arsip/My/coba-2x/1> === And here is my simple code: === public class Connector { private static Connection conn; private Connector() { try { Class.forName("com.mysql.jdbc.Driver"); conn = DriverManager.getConnection("jdbc:mysql://localhost/amt?user=root&password=pandawa5"); System.out.println("Connected"); } catch (ClassNotFoundException cnfe) { cnfe.printStackTrace(); } catch (SQLException sqle) { sqle.printStackTrace(); } } // Connection akan di-inisial sekali saja. public static Connection getConnection() { if (conn == null) { new Connector(); } return conn; } public static void closeConnection() { if (conn != null) { try { conn.close(); System.out.println("Disconnected"); } catch (SQLException sqle) { sqle.printStackTrace(); } } } } class Menu { //.... public static void customer() { PreparedStatement ps = null; try { Connection con = Connector.getConnection(); ps = con.prepareStatement("SELECT customerid FROM customer"); //..... } catch (SQLException sqle) { } finally { try { if (ps != null) ps.close(); } catch (SQLException sqle) { } } } } === Anybody would be so nice to teach me, please.... __________________________________ Do you Yahoo!? New Yahoo! Photos - easier uploading and sharing. http://photos.yahoo.com/

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How many posix threads?
by praisetazio 16 Dec '03

16 Dec '03

Hi all, I got this simple program creating 5 threads. #include <stdio.h> #include <stdlib.h> #include <pthread.h> void* donothing(void* n) { int i; for (;;i++) sleep(i); } int main() { pthread_t t[5]; int i = 0; for (i = 0; i<5; i++) pthread_create(&t[i], NULL, donothing, NULL); donothing(NULL); return 0; } Running this program, I see with ps xau, seven threads: praise 10557 92.3 0.1 11912 376 pts/3 R 17:09 0:30 ./a.out praise 10558 0.0 0.1 11912 376 pts/3 S 17:09 0:00 ./a.out praise 10559 0.0 0.1 11912 376 pts/3 S 17:09 0:00 ./a.out praise 10560 0.0 0.1 11912 376 pts/3 S 17:09 0:00 ./a.out praise 10561 0.0 0.1 11912 376 pts/3 S 17:09 0:00 ./a.out praise 10562 0.0 0.1 11912 376 pts/3 S 17:09 0:00 ./a.out praise 10563 0.0 0.1 11912 376 pts/3 S 17:09 0:00 ./a.out Why are they 7 and not 6? I create 5 threads, plus the main thread I thought I had to get 6 threads. Why I see 7 threads istead? Praise

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Free equivalent of Qt Designer for java
by John Lamb 16 Dec '03

16 Dec '03

Any suggestions to construct the code for a simple Swing applet GUI? -- JDL Non enim propter gloriam, diuicias aut honores pugnamus set propter libertatem solummodo quam Nemo bonus nisi simul cum vita amittit.

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Java and xemacs
by John Lamb 14 Dec '03

14 Dec '03

Can anyone suggest how I get JDE->compile to work in xemacs on 8.2? I'm using java for the first time in over a year and this feature is new to me. Currently I'm compiling from a shell with /usr/lib/SunJava2/bin/javac, but I'd like something a bit more like standard C/C++ compiling and I'm too used to C/C++/Perl/Python to give up xemacs. -- JDL Non enim propter gloriam, diuicias aut honores pugnamus set propter libertatem solummodo quam Nemo bonus nisi simul cum vita amittit.

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text file into array (c++)
by ged.suse＠ntlworld.com 12 Dec '03

12 Dec '03

How do I insert a textfile of stings, separated by carrige returns into an string array, or an array of pointers. I have been scratching my head over this for a while now and eventually have to turn for help. Here is as far as I have got, although I now know it won't work. ifstream fpi("names.dat"); char *name[5]; if (!fpi) { cout << "Error opening file\n"; exit(0); } for (int i=0; i<5; ++i) { fpi >> *(name+i); } for (int j=0; j<5; ++j) { cout << *(name+j) << endl; } fpi.close(); As you can see, i'm still pretty new to programming. Thanks, Ged. ----------------------------------------- Email provided by http://www.ntlhome.com/

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Re:[suse-programming-e] text file into array (c++)
by ged.suse＠ntlworld.com 12 Dec '03

12 Dec '03

Hi Axel, My understanding was that by using an array of pointers, you won't need to resize any arrays. The strings pointed to by the pointers will automatically resize to the length of the sting + 1 for the terminating char ('\0'). I have not read about vectors as yet, but they are sure to be next on my list. Thanks, Ged. > > From: <gigatronik.finger(a)daimlerchrysler.com> > Date: 2003/12/12 Fri AM 09:04:50 GMT > To: ged.suse(a)ntlworld.com > Subject: Antwort: [suse-programming-e] text file into array (c++) > > Hi Ged, > > I am struggeling with this problem too. First thing is that you should use > a vector. So you are not tied up in an array bounds. If your textfile > changes in length you have to recompile your code, because your array is > not big enough. Here is some sample code for acting with vectors: > > #include <iostream> > #include <vector> > > using namespace std; > > int main(int argc, char* argv[]) { > vector<int> vec; > > int i, p; > cout << "Anzahl eingeben: "; > cin >> p; > for(i = 0; i < p; i++) > vec.push_back(i); > > for(i = p; i > 0; i--) > cout << vec[i-1] <<" "; > } > > Benefit is that you can access the vector like an array and you are not > bound to any array restrictions. Resizing is done by the OS and you do not > have to bother about this. > > Mit freundlichen Grüßen, > Axel Finger > > > Erreichbar bei der Daimler-Chrysler AG unter: > Tel. > +49 (0)7031 / 90 - 41516 > Fax: > +49 (0)711 / 3052 163951 > E-Mail: > gigatronik.finger(a)daimlerchrysler.com > > > > > > > Axel Finger > DIAGNOSE (DI/TB) > > > > GIGATRONIK > Gesellschaft für Automobil- > elektronikentwicklung mbH > Hortensienweg 21 > 70374 Stuttgart > > > > > Tel: > +49 (0)711 / 84 96 09 - 0 > Fax: > +49 (0)711 / 84 96 09 - 99 > Email: > Axel.Finger(a)gigatronik.com > > > > > > > ged.suse(a)ntlworld.com > 12.12.2003 09:51 > Bitte antworten an ged.suse > > > > > An: suse-programming-e(a)suse.com > Kopie: > Thema: [suse-programming-e] text file into array (c++) > > How do I insert a textfile of stings, separated by carrige returns into an > string array, or an array of pointers. > > I have been scratching my head over this for a while now and eventually > have to turn for help. > > Here is as far as I have got, although I now know it won't work. > > ifstream fpi("names.dat"); > char *name[5]; > > if (!fpi) > { > cout << "Error opening file\n"; > exit(0); > } > > for (int i=0; i<5; ++i) > { > fpi >> *(name+i); > } > > for (int j=0; j<5; ++j) > { > cout << *(name+j) << endl; > } > > fpi.close(); > > As you can see, i'm still pretty new to programming. > > Thanks, > > Ged. > > ----------------------------------------- > Email provided by http://www.ntlhome.com/ > > > > -- > To unsubscribe, email: suse-programming-e-unsubscribe(a)suse.com > For additional commands, email: suse-programming-e-help(a)suse.com > Archives can be found at: http://lists.suse.com/archive/suse-programming-e > > > > > ----------------------------------------- Email provided by http://www.ntlhome.com/

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Passing a Connection variable between 2 different classes.
by Prabu Subroto 11 Dec '03

11 Dec '03

Dear my friends... I have 3 classes in my Java program One is Menu class, Konek (Connection) Class and Control Class. I want to put my connection code into one class but I don't know how to make another class can use the same connection, such as under below in my code.... I tried to pass the "conn" from koneksi.konek() like this : conn=koneksi.konek() but the output data type doesn't give me any possibility because the datatype of "conn" is Connection whereas I only may put : String, int, void etc. Should I use ADT in this case? Thanks in advance... ==== import java.sql.Connection; import java.sql.DriverManager; import java.sql.SQLException; import java.sql.*; class menu{ public static char start() { char pilihmenu; System.out.println("Here is customer menu\n\n"); System.out.println("========================================="); System.out.println("| Main Menu |"); System.out.println("========================================="); System.out.println("| Options : |"); System.out.println("| 1. Customer |"); System.out.println("| 2. Product Field |"); System.out.println("========================================="); pilihmenu = Keyin.inChar("Please choose (1-2) : "); return pilihmenu; } public static void customer() { try { koneksi.konek(); // Do something with the Connection // assume conn is an already created JDBC connection Statement stmt = null; ResultSet rs = null; try { //stmt = conn.createStatement(); //here is the problem. How can I make the "conn" connection variable be usable by this class and this method? In order to make my program can execute the query furthermore. I hate to make so many times Connection String in every time I need it. I want only in one method of one class. System.out.println("Executing query.\n"); rs = stmt.executeQuery("SELECT customerid FROM customer"); .... .... } finally { // it is a good idea to release // resources in a finally{} block // in reverse-order of their creation // if they are no-longer needed System.out.println("Error in Query.\n"); if (rs != null) { try { rs.close(); } catch (SQLException sqlEx) { // ignore } rs = null; } if (stmt != null) { try { stmt.close(); } catch (SQLException sqlEx) { // ignore } stmt = null; } } } } }catch (Exception e) { // handle any errors } } } class koneksi{ public static void konek(){ System.out.println("Building connection to database.\n"); try { Class.forName("com.mysql.jdbc.Driver").newInstance(); Connection conn = DriverManager.getConnection("jdbc:mysql://localhost/amt?user=root&password=pandawa5"); System.out.println("Connection established.: "+ conn+"\n"); // Do something with the Connection // assume conn is an already created JDBC connection }catch (Exception e) { // handle any errors System.out.println("Connection failed.\n"); } } } public class comadmin { public static void main(String[] args){ char pilihmenu; pilihmenu = menu.start(); System.out.println("Your choice is : "+pilihmenu+"\n"); if (pilihmenu== '1'){ System.out.println("Opening customer menu\n"); menu.customer(); } } } __________________________________ Do you Yahoo!? New Yahoo! Photos - easier uploading and sharing. http://photos.yahoo.com/

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[Fwd: Re: [suse-programming-e] Passing a Connection variable between 2 different classes.]
by expatriate 10 Dec '03

10 Dec '03

Prabu Subroto wrote: >Dear my friends... > >I have 3 classes in my Java program One is Menu class, >Konek (Connection) Class and Control Class. > >I want to put my connection code into one class but I >don't know how to make another class can use the same >connection, such as under below in my code.... > >I tried to pass the "conn" from koneksi.konek() like >this : conn=koneksi.konek() but the output data type >doesn't give me any possibility because the datatype >of "conn" is Connection whereas I only may put : >String, int, void etc. Should I use ADT in this case? > > <snip> I'm not sure I undestand the problem. I can create a class public class MyConnection { public MyConnection( String [] args) { ... //constructor } ...... public boolean runQuery(String [] args) { .................. } } and another class public class CompletelyDifferentClass { MyConnection myConn = null; CompletelyDifferentClass(MyConnection mc) { this.myConn = mc; } } and from another class do this public class Master { MyConnection myConn = null; CompletelyDifferentClass cdc = null; public MasterCreateQuery () { myConn = new MyConnection("whatever I have to do to get a connection"); boolean status = myConn.runQuery("anything"); cdc = new CompletelyDifferentClass(myConn); } } I routinely instantiate one connection to a server and use it persistently across many classes. HTH P.S. I fixed a couple of my own syntax errors

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Lost .pc files
by Tech Department 10 Dec '03

10 Dec '03

Any one know where the .pc configuration files for pkg-config have gone in suse 9.0 ? they are not in /usr/lib/pkgconfig. Atleast not the gtk group. To get the .pc file, I have been rebuilding the source packages and copying the .pc file to the pkgconfig dir. any information would be appreatiated.

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