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  • GoTo statements and alternatives in VB.NET

    - by qais
    I've posted a code snippet on another forum asking for help and people pointed out to me that using GoTo statements is very bad programming practice. I'm wondering: why is it bad? What alternatives to GoTo are there to use in VB.NET that would be considered generally more of a better practice? Consider this snippet below where the user has to input their date of birth. If the month/date/year are invalid or unrealistic(using if statements checking the integer inputs size, if there's a better way to do this, I'd appreciate if you could tell me that also :D) How would I be able to loop back to ask the user again? retryday: Console.WriteLine("Please enter the day you were born : ") day = Console.ReadLine If day > 31 Or day < 1 Then Console.WriteLine("Please enter a valid day") GoTo retryday End If

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  • SQL-wrappers (activerecord) to recommened for python?

    - by Horace Ho
    is there an activerecord (any similar SQL-wrapper) for python? which is good for: used in a server-side python script light-weight supports MySQL what I need to do: insert (filename, file size, file md5, the file itself) into (string, int, string, BLOB) columns if the same file (checksum + filename) does not exist in db thx

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  • Organising files and classes in XCode (iPhone application)

    - by pulegium
    It's a generic question and really a newbie one too, so bear with me... I'm playing with some iPhone development, and trying to create a simple "flip type" application. Nothing sophisticated, let's say on the flip side is a short application summary, bit like 'help' and on the main screen is a simple board game, let's say tic-tac-toe or similar. Now, XCode has generated me 'Main View', 'Flipside View' and 'Application Delegate' folders, with default template files in them. Now the question is where do I create appropriate 'MVC' classes? Let's say (V)iew classes are going to be the ones that have been automatically created. So the Flipside view class is responsible for generating text/images etc on the 'help' view. 'Main View' class is what draws the items on the table and updates the counters, etc. Where should I place the 'controller' class? And also, should it only be dealing with proxying only to the model? According to this the controller method is called from the view and manipulates the method classes. Similarly, the results from model are passed back to the view class by the controller issuing the calls to appropriate view methods. Similarly, where does the model class go? or should I just create a new folder for each, controller and model class files? What I'm after is the best practices, or just a short description how people normally structure their applications. I know it's very specific and also undefined... I came from Django background, so the way stuff is organised there is slightly different. Hope this makes sense, sorry if it's all bit vague, but I have to start somewhere :) And yes I've read quite few docs on the apple developer site, but trouble is that the documents are either going into too much detail about the language/framework/etc and the examples are way too simplistic. Actually, this leads me to the final question, has anyone know any good example of relatively complete application tutorial which I could use as a reference in organising my files?...

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  • When I overload the assignment operator for my simple class array, I get the wrong answer I espect

    - by user299648
    //output is "01234 00000" but the output should be or what I want it to be is // "01234 01234" because of the assignment overloaded operator #include <iostream> using namespace std; class IntArray { public: IntArray() : size(10), used(0) { a= new int[10]; } IntArray(int s) : size(s), used(0) { a= new int[s]; } int& operator[]( int index ); IntArray& operator =( const IntArray& rightside ); ~IntArray() { delete [] a; } private: int *a; int size; int used;//for array position }; int main() { IntArray copy; if( 2>1) { IntArray arr(5); for( int k=0; k<5; k++) arr[k]=k; copy = arr; for( int j=0; j<5; j++) cout<<arr[j]; } cout<<" "; for( int j=0; j<5; j++) cout<<copy[j]; return 0; } int& IntArray::operator[]( int index ) { if( index >= size ) cout<<"ilegal index in IntArray"<<endl; return a[index]; } IntArray& IntArray::operator =( const IntArray& rightside ) { if( size != rightside.size )//also checks if on both side same object { delete [] a; a= new int[rightside.size]; } size=rightside.size; used=rightside.used; for( int i = 0; i < used; i++ ) a[i]=rightside.a[i]; return *this; }

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  • How to rate a connect four game situation in java

    - by MrPink
    Hey, I am trying to write a simple AI for a "Get four" game. The basic game principles are done, so I can throw in coins of different color, and they stack on each other and fill a 2D Array and so on and so forth. until now this is what the method looks like: public int insert(int x, int color) //0 = empty, 1=player1 2=player2" X is the horizontal coordinate, as the y coordinate is determined by how many stones are in the array already, I think the idea is obvious. Now the problem is I have to rate specific game situations, so find how many new pairs, triplets and possible 4 in a row I can get in a specific situation to then give each situation a specific value. With these values I can setup a "Game tree" to then decide which move would be best next (later on implementing Alpha-Beta-Pruning). My current problem is that I can't think of an efficient way to implement a rating of the current game situation in a java method. Any ideas would be greatly appreciated! greetings from Germany Mr. Pink

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  • jQuery: What does (function($) {})(jQuery); mean?

    - by Legend
    I am just starting out with writing jQuery plugins. I wrote three small plugins but I have been simply copying the line into all my plugins without actually knowing what it means. Can someone tell me a little more about these? What does this do? (I know it extends jQuery somehow but is there anything else interesting to know about this) (function($) { })(jQuery); What is the difference between the following two ways of writing a plugin: Type 1: (function($) { $.fn.jPluginName = { }, $.fn.jPluginName.defaults = { } })(jQuery); Type 2: (function($) { $.jPluginName = { } })(jQuery); I could be way off here and maybe both mean the same thing. In some cases, this doesn't seem to be working in a plugin that I was writing using Type 1. Any idea why? But in either case, I would appreciate any explanation.

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  • MySQL::Eliminating redundant elements from a table?

    - by Legend
    I have a table like this: +-------+---------+------+-----+---------+-------+ | Field | Type | Null | Key | Default | Extra | +-------+---------+------+-----+---------+-------+ | v1 | int(11) | YES | MUL | NULL | | | v2 | int(11) | YES | MUL | NULL | | +-------+---------+------+-----+---------+-------+ There is a tremendous amount of duplication in this table. For instance, elements like the following: +------+------+ | v1 | v2 | +------+------+ | 1 | 2 | | 1 | 3 | | 1 | 4 | | 1 | 5 | | 1 | 6 | | 1 | 7 | | 1 | 8 | | 1 | 9 | | 2 | 1 | | 4 | 1 | | 5 | 1 | | 6 | 1 | | 7 | 1 | | 8 | 1 | | 9 | 1 | +------+------+ The table is large with 1540000 entries. To remove the redundant entries (i.e. to get a table having only (1,9) and no (9,1) entries), I was thinking of doing it with a subquery but is there a better way of doing this?

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  • An old flaw in X Window System. How does it work?

    - by Legend
    I was going through an article today when it mentioned the following: "We've found many errors over the years. One of the absolute best was the following in the X Window System: if(getuid() != 0 && geteuid == 0) { ErrorF("Only root"); exit(1); } It allowed any local user to get root access. (The tautological check geteuid == 0 was intended to be geteuid() == 0. In its current form, it compress the address of geteuid to 0; given that the function exists, its address is never 0)." The article explained what was wrong with the code but I would like to know what it means to say that "It allowed any local user to get root access". I am not an expert in C but can someone give me an exact context in which this exploit would work? Specifically, what I mean is, lets say I am the local user, how would I get root access if we assume this code to be present somewhere?

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  • Python text file processing speed issues

    - by Anonymouslemming
    Hi all, I'm having a problem with processing a largeish file in Python. All I'm doing is f = gzip.open(pathToLog, 'r') for line in f: counter = counter + 1 if (counter % 1000000 == 0): print counter f.close This takes around 10m25s just to open the file, read the lines and increment this counter. In perl, dealing with the same file and doing quite a bit more (some regular expression stuff), the whole process takes around 1m17s. Perl Code: open(LOG, "/bin/zcat $logfile |") or die "Cannot read $logfile: $!\n"; while (<LOG>) { if (m/.*\[svc-\w+\].*login result: Successful\.$/) { $_ =~ s/some regex here/$1,$2,$3,$4/; push @an_array, $_ } } close LOG; Can anyone advise what I can do to make the Python solution run at a similar speed to the Perl solution? I've tried just uncompressing the file and dealing with it using open instead of gzip.open, but that made a very small difference to the overall time.

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  • Where to start to learn Android?

    - by Tuffy G
    I want to start making a program for a local charity on the Android platform. Where can go I for resources and tutorials to learn? I'm very new at this, so would like something simple that can be followed by someone with minimal technical knowledge.

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  • An array problem in C++

    - by manugupt1
    To access the array indice at the xth position we can use some sort of illustration as shown below #include<iostream> using namespace std; int main(){ float i[20]; for(int j=0;j<=20;j++) i[j]=0; } However the following piece of code does not work #include<iostream> using namespace std; float oldrand[55]; int jrand; void advance_random(){ int j1; float new_random; for(j1=0;j1<=23;j1++){ int temp = j1+30; new_random = (oldrand[j1]) - (oldrand[temp]); if(new_random <0.0) new_random = new_random+1; oldrand[j1] = new_random; } for(j1=24;j1<=54;j1++){ new_random[j1] = oldrand[j1] - oldrand[j1-23]; if(new_random[j1]<0.0) new_random[j1] = new_random + 1; oldrand[j1]=new_random; } } I recieve the following error ga.cpp:20: error: invalid types ‘float[int]’ for array subscript ga.cpp:21: error: invalid types ‘float[int]’ for array subscript ga.cpp:22: error: invalid types ‘float[int]’ for array subscript I am not able to find a mistake in my code please help me

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  • How to pass objects to functions in C++?

    - by Rakesh K
    I am new to C++ programming, but I have experience in Java. I need guidance on how to pass objects to functions in C++. Do I need to pass pointers, references, or non-pointer and non-reference values? I remember in Java there are no such issues since we pass just the variable that holds reference to the objects. It would be great if you could also explain where to use each of those options.

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  • Python - output from functions?

    - by Seafoid
    Hi I have a very rudimentary question. Assume I call a function, e.g., def foo(): x = 'hello world' How do I get the function to return x in such a way that I can use it as the input for another function or use the variable within the body of a program? When I use return and call the variable within another functions I get a NameError. Thanks, S :-)

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  • C Array of string

    - by Meko
    HI. This is maybe simple question but I want to create two dimensional array and add it string like in java string str = "text" ; string [][] array = new [][] string ; array[i][j] = str ; But in C there is no string .I tried like this but here strcpy() gives error.It returns to assembly code. I am trying to read line by line from text and split line by space and add them to structure.But first I think that I must add each line and row in array and then making iteration and adding to structures fields. static const char filename[] = "student.txt"; FILE *file = fopen ( filename, "r" ); char line [ 128 ]; /* or other suitable maximum line size */ char delims [ ]=" "; char *result =NULL; char list[15]; char arra[128][128]; int i=0; int j=0; struct { char gruppa[10]; char familiya[20]; int uchaste; struct { int firsth; int second; int third; int fourht; int fifth; } exam; }student; for(i=0; i<128; i++) for(j=0; j<128; j++) arra[i][j] = '\0'; for(i=0; i<15; i++) list[i] = '\0'; if ( file != NULL ) { while ( fgets ( line, sizeof line, file ) != NULL ) { result = strtok(line,delims); while (result !=NULL) { strcpy(list,("%s",result)); strcpy(arra[i][j],list); // Here it gives errror j++; result = strtok(NULL,delims); } j=0; i++; } fclose ( file ); } else { perror ( filename ); } getchar(); return 0; }

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  • Unix: cannot add "\\ \n" even with escaping to the end of line

    - by HH
    I try to convert clean columnwise data to tables in tex. I am unable to have "\ \n" at each end of line. Please, see the command at the end. Data $ echo `. ./bin/addTableTexTags.sh < .data_3` 10.31 & 8.50 & 7.40 10.34 & 8.53 & 7.81 8.22 & 8.62 & 7.78 10.16 & 8.53 & 7.44 10.41 & 8.38 & 7.63 10.38 & 8.57 & 8.03 10.13 & 8.66 & 7.41 8.50 & 8.60 & 7.15 10.41 & 8.63 & 7.21 8.53 & 8.53 & 7.12 $ cat .data_3 10.31 8.50 7.40 10.34 8.53 7.81 8.22 8.62 7.78 10.16 8.53 7.44 10.41 8.38 7.63 10.38 8.57 8.03 10.13 8.66 7.41 8.50 8.60 7.15 10.41 8.63 7.21 8.53 8.53 7.12 addTableTexTags.sh #!/bin/bash sed -e "s@[[:space:]]@\t\&\t@g" -e "s@[[:space:]]*&*[[:space:]]*\$@\t \\ \\\\n@g" // Tried Escaping "\\" with "/" here and there // but cannot get a line ending with "\\ \n".

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  • Am I doing something wrong here (references in C++)?

    - by m4design
    I've been playing around with references (I'm still having issues in this regard). 1- I would like to know if this is an acceptable code: int & foo(int &y) { return y; // is this wrong? } int main() { int x = 0; cout << foo(x) << endl; foo(x) = 9; // is this wrong? cout << x << endl; return 0; } 2- Also this is from an exam sample: Week & Week::highestSalesWeek(Week aYear[52]) { Week max = aYear[0]; for(int i = 1; i < 52; i++) { if (aYear[i].getSales() > max.getSales()) max = aYear[i]; } return max; } It asks about the mistake in this code, also how to fix it. My guess is that it return a local reference. The fix is: Week & max = aYear[0]; Is this correct/enough?

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  • Including non-Python files with setup.py

    - by cool-RR
    How do I make setup.py include a file that isn't part of the code? (Specifically, it's a license file, but it could be any other thing.) I want to be able to control the location of the file. In the original source folder, the file is in the root of the package. (i.e. on the same level as the topmost __init__.py.) I want it to stay exactly there when the package is installed, regardless of operating system. How do I do that?

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  • python: equivalent to Javascript "||" to override non-truthful value

    - by Jason S
    In Javascript I can do this: function A(x) { return x || 3; } This returns 3 if x is a "non-truthful" value like 0, null, false, and it returns x otherwise. This is useful for empty arguments, e.g. I can do A() and it will evaluate as 3. Does Python have an equivalent? I guess I could make one out of the ternary operator a if b else c but was wondering what people use for this.

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  • Positioning Photos in a Grid (HTML)

    - by Daniel O'Connor
    Hey Everyone, I've been trying to code this page for a while, but my biggest problem is that I can't seem to get the photos perfectly positioned. For some reason, there is a small bottom padding in each <td>which is messing things up. Here is the table code: <table> <tr> <td rowspan="2" style="height:353px;"><img src="danoconnor/img/photography/farm.jpg" height="353" width="470" alt="Farm" /></td> <td><img src="danoconnor/img/photography/paragliding.jpg" height="190" width="254" alt="Paraglider" /></td> <td rowspan="2"><img src="danoconnor/img/photography/cristo.jpg" height="353" width="230" alt="Cristo Redentor" /></td> </tr> <tr> <td><img src="danoconnor/img/photography/u2.jpg" height="154" width="254" alt="U2 at Fordham University" /></td> </tr> </table> My question is: how can I make the photogrid look like this? Thanks!

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  • How to provide global functionality in multi-user database app

    - by Mike B
    I have been building a multi-user database application (in C#/WPF 4.0) that manages tasks for all employees of a company. I now need to add some functionality such as sending an email reminder to someone when a critical task is due. How should this be done? Obviously I don’t want every instance of the program to be performing this function (Heh each user would get 10+ emails). Should I add the capability to the application as a "Mode" and then run a copy on the database server in this mode or would it be better to create a new app altogether to perform "Global" type tasks? Is there a better way?

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