The Official Programming Thread

asad3man · Apr 19, 2016

Newton said:
that entirely depends on your approach towards programming. for a very basic solution i would

take a piece of paper and a pencil

sketch a pacman map on it

brain storm what possible way i can represent it in my code

i may use a 2D array of 1s and 0s where 1s will represent a wall and 0s represent an open space

navigation methods can use the 0/1s to allow or block movement

1 1 1 1 1
1 0 0 1 1
1 1 0 0 1
1 0 0 0 1
1 1 1 1 1

color up the 1s only in the above table and you will get how i represented a map

Okay I got this thing. But what about the approach, after making this map. Can you make a class or two to explain me. Any two class?

Newton · Apr 19, 2016

asad3man said:
Okay I got this thing. But what about the approach, after making this map. Can you make a class or two to explain me. Any two class?

sorry man dont have time for the next 3 weeks or so. after that yes

EternalBlizzard · Apr 21, 2016

Ok next up is my Image Processing project i did in my 2nd semester. Noise removal through Vector Median filter and Edge detection through Sobel-Feldmen Operator....

@puppet
Kesa

?
Images aren't working for some reason, here is the link to the album
http://imgur.com/a/paB2a ( watch it in full size and you'll notice how noise is reduces)

Spoiler: show

Newton · May 11, 2016

anyone here has experience with MongoDB? especially using it with JAVA..

thugslife · Jun 4, 2016

Hey guys i really need some help regarding a debug I am creating a POS application but I am stuck at some point the checkout class is making some problem and I am unable to figure out the problem

the error is

Exception in thread "main" java.lang.NullPointerException
at controller.ShoppingCart.checkOut(ShoppingCart.java:75)
at pos1.POSApp.main(POSApp.java:31)

following link contains the rar file for the project file
https://drive.google.com/file/d/0B3aPDdCOdAHARDZxMktSV0IxYms/view?usp=sharing

@Newton @asad3man @Eternal Blizzard@staticPointer

Newton · Jun 4, 2016

thugslife said:
Hey guys i really need some help regarding a debug I am creating a POS application but I am stuck at some point the checkout class is making some problem and I am unable to figure out the problem

the error is

Exception in thread "main" java.lang.NullPointerException
at controller.ShoppingCart.checkOut(ShoppingCart.java:75)
at pos1.POSApp.main(POSApp.java:31)

following link contains the rar file for the project file
https://drive.google.com/open?id=0B3aPDdCOdAHARDZxMktSV0IxYms

@Newton @asad3man @Eternal Blizzard@staticPointer

Please explain what your project is trying to do in a few simple lines. I'll look at your code sometime after lunch today

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EternalBlizzard · Jun 4, 2016

thugslife said:
Hey guys i really need some help regarding a debug I am creating a POS application but I am stuck at some point the checkout class is making some problem and I am unable to figure out the problem

the error is

Exception in thread "main" java.lang.NullPointerException
at controller.ShoppingCart.checkOut(ShoppingCart.java:75)
at pos1.POSApp.main(POSApp.java:31)

following link contains the rar file for the project file
https://drive.google.com/open?id=0B3aPDdCOdAHARDZxMktSV0IxYms

@Newton @asad3man @Eternal Blizzard@staticPointer

Try debug it yourself. Read on the net why Null pointer exception is thrown and what it is. You might be trying to use an uninitialized object reference

thugslife · Jun 4, 2016

Newton said:
Please explain what your project is trying to do in a few simple lines. I'll look at your code sometime after lunch today

Sent from my LG-H818 using Tapatalk

It consist of a local file consisting of items with price currency and id the user will prompt to enter product id`s which will be added to cart then proceed to checkout .. but the problem is whenever I finish adding items to the cart and exit to the checkout the Null Point exception occurs the problem lies in the ShoppingCart Class in which there is a method CheckOut()

- - - Updated - - -

Eternal Blizzard said:
Try debug it yourself. Read on the net why Null pointer exception is thrown and what it is. You might be trying to use an uninitialized object reference

before posting i tried every expect of debugging

after I lost faith in myself i posted here

EternalBlizzard · Jun 4, 2016

thugslife said:
before posting i tried every expect of debugging after I lost faith in myself i posted here

that link ain't working requires permission

thugslife · Jun 4, 2016

Eternal Blizzard said:
that link ain't working requires permission

let me post again
[url]https://drive.google.com/file/d/0B3aPDdCOdAHARDZxMktSV0IxYms/view?usp=sharing
[/URL]

EternalBlizzard · Jun 4, 2016

thugslife said:
let me post again
https://drive.google.com/file/d/0B3aPDdCOdAHARDZxMktSV0IxYms/view?usp=sharing

All i can infer is that one or more items in the list don't have their Price set. so when you try to do .getPrice() it returns a null pointer exception.

thugslife · Jun 4, 2016

Eternal Blizzard said:
All i can infer is that one or more items in the list don't have their Price set. so when you try to do .getPrice() it returns a null pointer exception.

https://drive.google.com/file/d/0B3aPDdCOdAHARDFCRF8yU2JJSE0/view?usp=sharing

every item have price

EternalBlizzard · Jun 4, 2016

thugslife said:
https://drive.google.com/file/d/0B3aPDdCOdAHARDFCRF8yU2JJSE0/view?usp=sharing

every item have price

Did you run the debugger? Run a test with 3 items. Check when the null pointer exception occurs? after 3rd time or before?

Newton · Jun 5, 2016

thugslife said:
https://drive.google.com/file/d/0B3aPDdCOdAHARDFCRF8yU2JJSE0/view?usp=sharing

every item have price

I'm having a look at your code today. Please write down a simple program flow in a few lines or a small flow chart. Tell me how it flows from the main navigating through which classes for what functionality

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Newton · Jun 5, 2016

@thugslife
i went through your code. the issue is in the below method loadItemDetails

Code:

public ArrayList<Item> loadItemDetails(ArrayList<String> itemIds) {

 ArrayList<Item> purchasedItemList = new ArrayList<Item>();


 //read all the available item map
 ItemManager itemManager = new ItemManager();
 HashMap<String,Item> allItems = itemManager.getAllItems();

 for (int i = 0; i < itemIds.size(); i++) {
  String index = (String)itemIds.get(i);
  System.out.println(allItems.keySet());
  [COLOR=#ff0000]Item temp = allItems.get("\"i1");[/COLOR]
  purchasedItemList.add(temp);
 }
 return purchasedItemList;
}

the keys which you are storing in your HashMap are not i1, i2, i3 but they are "i1, "i2 and "i3. look at the red line above and you will understand the issue. I hope this helps.

EDIT : ignore the extra stuff i added for testing

lastsamurai · Aug 16, 2016

Guys stackoverflow is also a good site for programming queries.

EternalBlizzard · Aug 16, 2016

lastsamurai said:
gO FOR STACKOVERFLOW.COM...it contains answer to all the errors faced in programming life.

everybody knows that. There are specific forums for everything, that doesn't mean we shouldn't discuss those topics here. PG isn't just a gaming forum, its much more than that.

AsadAbrar · Aug 16, 2016

Guys, which language should i learn which would help me later when i complete my BS CS degree?
I'm a noob and i just started html from codecademy.

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EternalBlizzard · Aug 16, 2016

AsadAbrar said:
Guys, which language should i learn which would help me later when i complete my BS CS degree?
I'm a noob and i just started html from codecademy.

Sent from my HUAWEI VNS-L21 using Tapatalk

Depends on what you actually want to do later on... BW shared an image here lemme reupload it...

Spoiler: show

And it greatly helps if you pick C/C++ cuz it's a general purpose language so its used in most places. My uni didn't teach me C/C++ so im learning by myself as its feels awkward to say i don't know C/C++ but know other high level languages like Java and C# ;s

That aside the main thing for beginners is to grasp the logic. Loops/functions/structures etc. When you grasp the concepts switching languages is easy as a pie.

Also HTML is completely different. It's not your typical programming language and most ppl don't even consider it one.

djkk16 · Aug 17, 2016

Eternal Blizzard said:
Depends on what you actually want to do later on... BW shared an image here lemme reupload it...

Spoiler: show

And it greatly helps if you pick C/C++ cuz it's a general purpose language so its used in most places. My uni didn't teach me C/C++ so im learning by myself as its feels awkward to say i don't know C/C++ but know other high level languages like Java and C# ;s

That aside the main thing for beginners is to grasp the logic. Loops/functions/structures etc. When you grasp the concepts switching languages is easy as a pie.

Also HTML is completely different. It's not your typical programming language and most ppl don't even consider it one.

Nice share mate.

Currently learning c++ myself with the help of a good book and doing practice programs.

Where are you learning it from ?

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