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Thread Rules 1. This is not a "do my homework for me" thread. If you have specific questions, ask, but don't post an assignment or homework problem and expect an exact solution. 2. No recruiting for your cockamamie projects (you won't replace facebook with 3 dudes you found on the internet and $20) 3. If you can't articulate why a language is bad, don't start slinging shit about it. Just remember that nothing is worse than making CSS IE6 compatible. 4. Use [code] tags to format code blocks. |
On September 12 2011 11:07 f0rzaa wrote: I think this was the first example of the class(C++) intro:
#include <iostream>
using namespace std;
int main() { cout << "Hello world!" << endl; return 0; }
I realize this might be extremely simple but I was playing around with Codeblocks and I seem to get the same thing with or without the return 0;. Hello world! is printed either way.
So basically my question is why's it work with and without it if it's needed?
I don't know if this has been said already (was just browsing through old posts), but with the brand new shiny c++ you actually don't need to put return 0;.
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On October 10 2011 01:55 kollin wrote: I don't know if this has been said already (was just browsing through old posts), but with the brand new shiny c++ you actually don't need to put return 0;.
You didn't need to in the '98 C++ standard either. However, it's not harmful, and it might be a decent habit to get into (putting it there) both for explicitness's sake and because it is required in C.
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@Frigo if your NodeVector and EdgeVector classes are implementations of Vectors, you're already in n^2 time. You can go to linear time by turning them into, say, a HashMap.
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HAHA!
Managed to create an observer pattern in Java that does not require the user to manually unsubscribe each observer from the observable object, and does not leak memory either.
http://frigocoder.dyndns.org/svn/jfrigo/util/Observable.java http://frigocoder.dyndns.org/svn/jfrigo/util/Observer.java http://frigocoder.dyndns.org/svn/jfrigo/util/ComparableWeakReference.java
On October 10 2011 10:29 BottleAbuser wrote: @Frigo if your NodeVector and EdgeVector classes are implementations of Vectors, you're already in n^2 time. You can go to linear time by turning them into, say, a HashMap.
I thought Vectors have amortized constant insertion time? Both are based on Vector and its add method.
As for the Observer set, I plan on creating a HashTreeSet which is just basically a hash table with a self-balancing binary tree in each bucket instead of a list. O(1) average access, O(log n) worst case access with poor hash functions. Too difficult at the moment though, I'm still a noobie java progger.
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Could someone recommend goods books for Software Engineering(I know about Code Completed), Computer Science(math side, machine code, ai) and hardware books(hardware construction or w/e, just want to get good picture), if possible books that are used in university, i am fairly experienced .NET and C++ developer. Thanks a lot!
~ P.S. Awesome thread!
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On October 12 2011 02:00 LionKiNG wrote: Could someone recommend goods books for Software Engineering(I know about Code Completed), Computer Science(math side, machine code, ai) and hardware books(hardware construction or w/e, just want to get good picture), if possible books that are used in university, i am fairly experienced .NET and C++ developer. Thanks a lot!
~ P.S. Awesome thread!
AI: Artificial Intelligence: A Modern Approach by Stuart Russell and Peter Norvig
It's _the_ basic AI book we use in all lectures in university. Keep in mind: only pseudocode.
About math: What kind of math, try to be more specific
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On October 12 2011 02:12 Zocat wrote:Show nested quote +On October 12 2011 02:00 LionKiNG wrote: Could someone recommend goods books for Software Engineering(I know about Code Completed), Computer Science(math side, machine code, ai) and hardware books(hardware construction or w/e, just want to get good picture), if possible books that are used in university, i am fairly experienced .NET and C++ developer. Thanks a lot!
~ P.S. Awesome thread! AI: Artificial Intelligence: A Modern Approach by Stuart Russell and Peter Norvig It's _the_ basic AI book we use in all lectures in university. Keep in mind: only pseudocode. About math: What kind of math, try to be more specific 
Thanks a lot, i will check that book out and maybe order it, as for math, well mostly math that is used in "Computer Science" courses.
Also another question is W3School certification worth its money or complete b/s?
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On October 12 2011 02:17 LionKiNG wrote:Show nested quote +On October 12 2011 02:12 Zocat wrote:On October 12 2011 02:00 LionKiNG wrote: Could someone recommend goods books for Software Engineering(I know about Code Completed), Computer Science(math side, machine code, ai) and hardware books(hardware construction or w/e, just want to get good picture), if possible books that are used in university, i am fairly experienced .NET and C++ developer. Thanks a lot!
~ P.S. Awesome thread! AI: Artificial Intelligence: A Modern Approach by Stuart Russell and Peter Norvig It's _the_ basic AI book we use in all lectures in university. Keep in mind: only pseudocode. About math: What kind of math, try to be more specific  Thanks a lot, i will check that book out and maybe order it, as for math, well mostly math that is used in "Computer Science" courses. There are many math courses that you take during CS studies. Mathematical analysis, geometry, linear algebra, probability, statistics, discrete mathematics and also several algorithm courses (I guess this is theoretical computer science and not math, though). This isn't high school, you can't just buy a "math book" :>
If you don't have any knowledge about algorithms, I'd suggest focusing on that first. Cormen's book seems to be something that's recommended by every professor/lecturer.
Also another question is W3School certification worth its money or complete b/s? I doubt it's worth it. W3schools seems to be just a random website with html documentation (incorrect in many places, too).
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On October 12 2011 04:15 delHospital wrote:Show nested quote +On October 12 2011 02:17 LionKiNG wrote:On October 12 2011 02:12 Zocat wrote:On October 12 2011 02:00 LionKiNG wrote: Could someone recommend goods books for Software Engineering(I know about Code Completed), Computer Science(math side, machine code, ai) and hardware books(hardware construction or w/e, just want to get good picture), if possible books that are used in university, i am fairly experienced .NET and C++ developer. Thanks a lot!
~ P.S. Awesome thread! AI: Artificial Intelligence: A Modern Approach by Stuart Russell and Peter Norvig It's _the_ basic AI book we use in all lectures in university. Keep in mind: only pseudocode. About math: What kind of math, try to be more specific  Thanks a lot, i will check that book out and maybe order it, as for math, well mostly math that is used in "Computer Science" courses. There are many math courses that you take during CS studies. Mathematical analysis, geometry, linear algebra, probability, statistics, discrete mathematics and also several algorithm courses (I guess this is theoretical computer science and not math, though). This isn't high school, you can't just buy a "math book" :> If you don't have any knowledge about algorithms, I'd suggest focusing on that first. Cormen's book seems to be something that's recommended by every professor/lecturer. Show nested quote +Also another question is W3School certification worth its money or complete b/s? I doubt it's worth it. W3schools seems to be just a random website with html documentation (incorrect in many places, too).
I got knowledge in both algorithms and most of those math parts( Probability and statistics left, i am high school), thanks tho.
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Hey guys, same question from me in spoiler. Was wondering if anyone had any ideas because I'm still looking 
+ Show Spoiler +On October 05 2011 06:43 renox wrote: Hey guys,
I'm currently a first year computer science student and I am in need of a job. What would you guys suggest I look for to benefit me in this field? Is there anything that I would even qualify for just being a first year student? Any and all advice would be lovely, share personal experiences of working during school etc. On October 05 2011 08:05 renox wrote:Show nested quote +On October 05 2011 07:18 tofucake wrote: Almost any work you'll get as a first year student will be bitch work and there's no way around it.
Is this going to be a job you do for school (co-op program) or just something you'll do in your spare time? Well I need a job just to have money and for my expenses, but I was wondering if there was something I could do that would later be useful to me in some way in regards to this field. So I was wondering if you guys have had some luck like this or experience with it. I mean I could get some random job like most college students but I figured if I could tie it into the field I want to study somehow it would benefit me because I may find it interesting but also be an asset to my career down the road.
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On October 04 2011 09:24 Millitron wrote:Show nested quote +On October 04 2011 05:12 Thorakh wrote:95% of all programmers couldn't write maintainable code if their life depended on it I always hear people talking about this, but what do you exactly mean by that? Can you give any examples? Most people are bad about commenting there work, and even when they do, the comments aren't very explanatory. Further, maintainable code needs commonly used variables defined globally, rather than each time its needed, so you can update it in only one spot and be done with it. Last, variables should be well-named. Unless it's some loop-control variable you'll never use again, you should never name things with a single character. Always use more descriptive names. Well lucky me, I hate writing code that doesn't do all those things 
A question, I'm currently steering my CS study in the direction of lowlevel code+hardware design, how is the job availability in this field? I'm planning to do my minor in electrical engineering. I'd imagine that I'll have a better job prospect in this field than in software design (based on seeing the overwhelming majority of other students choose the highlevel route).
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On October 12 2011 02:17 LionKiNG wrote: Also another question is W3School certification worth its money or complete b/s?
Absolutely NOT. Although W3schools has its usefulness for beginners, its full of errors and is quite outdated. I dont believe their certification has any value at all.
See also: http://w3fools.com/
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Another questions, what books would u recommend for mufti-platform C++ programming?
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Hey guys
I've been busy with a project for school, and I've stumbled upon an error and was wondering how I could get rid of it.
Error message:
Exception in thread "main" java.lang.NullPointerException at businessunits.BusinessUnitsApp.readSensorValue(BusinessUnitsApp.java:225)
(I'm working with Java in Netbeans)
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On October 12 2011 05:59 Quasimomo wrote: Hey guys
I've been busy with a project for school, and I've stumbled upon an error and was wondering how I could get rid of it.
Error message:
Exception in thread "main" java.lang.NullPointerException at businessunits.BusinessUnitsApp.readSensorValue(BusinessUnitsApp.java:225)
(I'm working with Java in Netbeans)
I believe BusinessUnitsApp has null value in that case, and that is causing a problem, adding check before code will fix error however, not problem, you should try debugging and see why BusinessUnitsApp gets null value passed.
EDIT: Also sharing peace of code with us would greatly help us solve your problem
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On October 12 2011 04:24 renox wrote:Hey guys, same question from me in spoiler. Was wondering if anyone had any ideas because I'm still looking + Show Spoiler +On October 05 2011 06:43 renox wrote: Hey guys,
I'm currently a first year computer science student and I am in need of a job. What would you guys suggest I look for to benefit me in this field? Is there anything that I would even qualify for just being a first year student? Any and all advice would be lovely, share personal experiences of working during school etc. On October 05 2011 08:05 renox wrote:Show nested quote +On October 05 2011 07:18 tofucake wrote: Almost any work you'll get as a first year student will be bitch work and there's no way around it.
Is this going to be a job you do for school (co-op program) or just something you'll do in your spare time? Well I need a job just to have money and for my expenses, but I was wondering if there was something I could do that would later be useful to me in some way in regards to this field. So I was wondering if you guys have had some luck like this or experience with it. I mean I could get some random job like most college students but I figured if I could tie it into the field I want to study somehow it would benefit me because I may find it interesting but also be an asset to my career down the road.
Your best bet might be a research position at the university. I worked in a lab that did posture prediction when I was in school and they hired a lot of undergrads for the user interfaces and testing because CS/Engineering students are smart and you can pay them much less than a grad student or professional. And its good for you because you get professional programming experience.
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On October 12 2011 06:25 LionKiNG wrote:Show nested quote +On October 12 2011 05:59 Quasimomo wrote: Hey guys
I've been busy with a project for school, and I've stumbled upon an error and was wondering how I could get rid of it.
Error message:
Exception in thread "main" java.lang.NullPointerException at businessunits.BusinessUnitsApp.readSensorValue(BusinessUnitsApp.java:225)
(I'm working with Java in Netbeans) I believe BusinessUnitsApp has null value in that case, and that is causing a problem, adding check before code will fix error however, not problem, you should try debugging and see why BusinessUnitsApp gets null value passed. EDIT: Also sharing peace of code with us would greatly help us solve your problem 
Hmmm... There is quite a bit of code. and the OP said I wasn't supposed to post a wall of text. Is there maybe another way to show you?
Maybe if I give some extra information about it: I'm working with a GUI that launches when running and it's controlled by using several phidgets. It's also linked with VLC player to start a movie at the start. And the debug didn't help/work
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On October 12 2011 07:04 Quasimomo wrote:Show nested quote +On October 12 2011 06:25 LionKiNG wrote:On October 12 2011 05:59 Quasimomo wrote: Hey guys
I've been busy with a project for school, and I've stumbled upon an error and was wondering how I could get rid of it.
Error message:
Exception in thread "main" java.lang.NullPointerException at businessunits.BusinessUnitsApp.readSensorValue(BusinessUnitsApp.java:225)
(I'm working with Java in Netbeans) I believe BusinessUnitsApp has null value in that case, and that is causing a problem, adding check before code will fix error however, not problem, you should try debugging and see why BusinessUnitsApp gets null value passed. EDIT: Also sharing peace of code with us would greatly help us solve your problem  Hmmm... There is quite a bit of code. and the OP said I wasn't supposed to post a wall of text. Is there maybe another way to show you? Maybe if I give some extra information about it: I'm working with a GUI that launches when running and it's controlled by using several phidgets. It's also linked with VLC player to start a movie at the start. And the debug didn't help/work 
Try putting it in spoilers
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Derp! Of course hahaha xD
Here is the whole code that's causing the problems ( I think ) I'm working with a few other .java files. These include the GUI file and the file that takes care of linking vlc to java.
+ Show Spoiler + package businessunits;
import com.phidgets.*;
import java.awt.AWTException; import java.awt.Robot; import java.awt.event.InputEvent; import org.jdesktop.application.Application; import org.jdesktop.application.SingleFrameApplication;
public class BusinessUnitsApp extends SingleFrameApplication { @Override protected void startup() { show(new BusinessUnitsView(this)); }
/** * This method is to initialize the specified window by injecting resources. * Windows shown in our application come fully initialized from the GUI * builder, so this additional configuration is not needed. */ @Override protected void configureWindow(java.awt.Window root) { }
/** * A convenient static getter for the application instance. * @return the instance of BusinessUnitsApp */ public static BusinessUnitsApp getApplication() { return Application.getInstance(BusinessUnitsApp.class); }
/** * Main method launching the application. */ VLCv2 vlc = new VLCv2("localhost", 1234); private Phidget phidget; private BusinessUnitsView guiobj; private InterfaceKitPhidget interf;
/** * constructor van deze Main klasse, maak GUI aan en * maak verbinding met VLC */
public long getsensor(int a) { long sensor = readSensorValue(a);
return sensor; }
public boolean getdeurbel() { boolean deurbel = Inputstate(0); return deurbel;
}
//Vanaf 120 public long StartMove() {
long sensor7 = readSensorValue(7); return sensor7;
}
public boolean deurbel() { while (true) { try { boolean deurbel = Inputstate(0); Thread.sleep(250); System.out.println(deurbel); if (deurbel) { return deurbel; } } catch (Exception e) { e.printStackTrace(); } } }
public static void main(String[] args) throws InterruptedException { launch(BusinessUnitsApp.class, args);
BusinessUnitsApp m = new BusinessUnitsApp(); VLCv2 vlc = new VLCv2("localhost", 1234);
vlc.connect(); vlc.rc.fullscreen(); vlc.rc.play(); vlc.rc.pause();
while (true) { try {
Robot rob = new Robot(); Thread.sleep(250); long sensor7 = m.StartMove();
if (sensor7 >= 70) { vlc.rc.play();
for (int i = 0; i <= 110; i++) { Thread.sleep(1000); System.out.println(i); if (i == 110) { vlc.rc.pause(); } } }
if (m.getsensor(0) < 100) { rob.mouseMove(1550, 340); rob.mousePress(InputEvent.BUTTON1_MASK); rob.mouseRelease(InputEvent.BUTTON1_MASK);
}
if (m.getsensor(1) < 100) { rob.mouseMove(1550, 410); rob.mousePress(InputEvent.BUTTON1_MASK); rob.mouseRelease(InputEvent.BUTTON1_MASK);
}
if (m.getsensor(2) < 100) { rob.mouseMove(1550, 470); rob.mousePress(InputEvent.BUTTON1_MASK); rob.mouseRelease(InputEvent.BUTTON1_MASK);
}
if (m.getsensor(3) < 100) { rob.mouseMove(1550, 535); rob.mousePress(InputEvent.BUTTON1_MASK); rob.mouseRelease(InputEvent.BUTTON1_MASK);
}
if (m.getsensor(4) < 100) { rob.mouseMove(1550, 600); rob.mousePress(InputEvent.BUTTON1_MASK); rob.mouseRelease(InputEvent.BUTTON1_MASK);
}
if (m.getsensor(5) < 100) { rob.mouseMove(1550, 650); rob.mousePress(InputEvent.BUTTON1_MASK); rob.mouseRelease(InputEvent.BUTTON1_MASK);
}
if (m.getdeurbel()) { vlc.rc.play();
for (int a = 0; a <= 126; a++) { Thread.sleep(1000); System.out.print(a + " ");
if (a == 44) { vlc.rc.pause(); while (true) { try { boolean deurbel = m.deurbel(); if (deurbel == true) { vlc.rc.play(); break; } } catch (Exception e) { e.printStackTrace(); } } } if (a == 126){ vlc.rc.pause(); } } }
} catch (AWTException e) { e.printStackTrace(); } } }
public void makeConnection() {
try { //interf.openAny("localhost", 5001); // alleen voor webservice-versie interf.openAny(); // werkt ook zonder webservice interf.waitForAttachment(1000); // 1 sec, anders exception } catch (PhidgetException e) { e.printStackTrace(); } }// end of phidgetmakeConnection() //public native boolean getInputState(int i) throws PhidgetException;
public boolean Inputstate(int nr) { boolean value = false; try { value = interf.getInputState(nr); } catch (PhidgetException e) { e.printStackTrace(); } return value;
}
public long readSensorValue(int nr) { long value = -1; try { value = interf.getSensorValue(nr); } catch (PhidgetException e) { e.printStackTrace(); } return value; }
public void setOutputValue(int nr, Boolean state) { try { interf.setOutputState(nr, state); } catch (PhidgetException e) { e.printStackTrace(); } } }
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On October 12 2011 07:17 Quasimomo wrote:Derp! Of course hahaha xD Here is the whole code that's causing the problems ( I think ) I'm working with a few other .java files. These include the GUI file and the file that takes care of linking vlc to java. + Show Spoiler + package businessunits;
import com.phidgets.*;
import java.awt.AWTException; import java.awt.Robot; import java.awt.event.InputEvent; import org.jdesktop.application.Application; import org.jdesktop.application.SingleFrameApplication;
public class BusinessUnitsApp extends SingleFrameApplication { @Override protected void startup() { show(new BusinessUnitsView(this)); }
/** * This method is to initialize the specified window by injecting resources. * Windows shown in our application come fully initialized from the GUI * builder, so this additional configuration is not needed. */ @Override protected void configureWindow(java.awt.Window root) { }
/** * A convenient static getter for the application instance. * @return the instance of BusinessUnitsApp */ public static BusinessUnitsApp getApplication() { return Application.getInstance(BusinessUnitsApp.class); }
/** * Main method launching the application. */ VLCv2 vlc = new VLCv2("localhost", 1234); private Phidget phidget; private BusinessUnitsView guiobj; private InterfaceKitPhidget interf;
/** * constructor van deze Main klasse, maak GUI aan en * maak verbinding met VLC */
public long getsensor(int a) { long sensor = readSensorValue(a);
return sensor; }
public boolean getdeurbel() { boolean deurbel = Inputstate(0); return deurbel;
}
//Vanaf 120 public long StartMove() {
long sensor7 = readSensorValue(7); return sensor7;
}
public boolean deurbel() { while (true) { try { boolean deurbel = Inputstate(0); Thread.sleep(250); System.out.println(deurbel); if (deurbel) { return deurbel; } } catch (Exception e) { e.printStackTrace(); } } }
public static void main(String[] args) throws InterruptedException { launch(BusinessUnitsApp.class, args);
BusinessUnitsApp m = new BusinessUnitsApp(); VLCv2 vlc = new VLCv2("localhost", 1234);
vlc.connect(); vlc.rc.fullscreen(); vlc.rc.play(); vlc.rc.pause();
while (true) { try {
Robot rob = new Robot(); Thread.sleep(250); long sensor7 = m.StartMove();
if (sensor7 >= 70) { vlc.rc.play();
for (int i = 0; i <= 110; i++) { Thread.sleep(1000); System.out.println(i); if (i == 110) { vlc.rc.pause(); } } }
if (m.getsensor(0) < 100) { rob.mouseMove(1550, 340); rob.mousePress(InputEvent.BUTTON1_MASK); rob.mouseRelease(InputEvent.BUTTON1_MASK);
}
if (m.getsensor(1) < 100) { rob.mouseMove(1550, 410); rob.mousePress(InputEvent.BUTTON1_MASK); rob.mouseRelease(InputEvent.BUTTON1_MASK);
}
if (m.getsensor(2) < 100) { rob.mouseMove(1550, 470); rob.mousePress(InputEvent.BUTTON1_MASK); rob.mouseRelease(InputEvent.BUTTON1_MASK);
}
if (m.getsensor(3) < 100) { rob.mouseMove(1550, 535); rob.mousePress(InputEvent.BUTTON1_MASK); rob.mouseRelease(InputEvent.BUTTON1_MASK);
}
if (m.getsensor(4) < 100) { rob.mouseMove(1550, 600); rob.mousePress(InputEvent.BUTTON1_MASK); rob.mouseRelease(InputEvent.BUTTON1_MASK);
}
if (m.getsensor(5) < 100) { rob.mouseMove(1550, 650); rob.mousePress(InputEvent.BUTTON1_MASK); rob.mouseRelease(InputEvent.BUTTON1_MASK);
}
if (m.getdeurbel()) { vlc.rc.play();
for (int a = 0; a <= 126; a++) { Thread.sleep(1000); System.out.print(a + " ");
if (a == 44) { vlc.rc.pause(); while (true) { try { boolean deurbel = m.deurbel(); if (deurbel == true) { vlc.rc.play(); break; } } catch (Exception e) { e.printStackTrace(); } } } if (a == 126){ vlc.rc.pause(); } } }
} catch (AWTException e) { e.printStackTrace(); } } }
public void makeConnection() {
try { //interf.openAny("localhost", 5001); // alleen voor webservice-versie interf.openAny(); // werkt ook zonder webservice interf.waitForAttachment(1000); // 1 sec, anders exception } catch (PhidgetException e) { e.printStackTrace(); } }// end of phidgetmakeConnection() //public native boolean getInputState(int i) throws PhidgetException;
public boolean Inputstate(int nr) { boolean value = false; try { value = interf.getInputState(nr); } catch (PhidgetException e) { e.printStackTrace(); } return value;
}
public long readSensorValue(int nr) { long value = -1; try { value = interf.getSensorValue(nr); } catch (PhidgetException e) { e.printStackTrace(); } return value; }
public void setOutputValue(int nr, Boolean state) { try { interf.setOutputState(nr, state); } catch (PhidgetException e) { e.printStackTrace(); } } }
As far as I can see you call the method getSensorValue on the interf variable which is no initialized and therefore throws a NullpointerException. You need to do something like inter = new InterfaceKitPhidget(); before calling methods on it.
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