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  • "Address of" (&) an array / address of being ignored be gcc?

    - by dbarbosa
    Hi, I am a teaching assistant of a introductory programming course, and some students made this type of error: char name[20]; scanf("%s",&name); which is not surprising as they are learning... What is surprising is that, besides gcc warning, the code works (at least this part). I have been trying to understand and I wrote the following code: void foo(int *str1, int *str2) { if (str1 == str2) printf("Both pointers are the same\n"); else printf("They are not the same\n"); } int main() { int test[50]; foo(&test, test); if (&test == test) printf("Both pointers are the same\n"); else printf("They are not the same\n"); } Compiling and executing: $ gcc test.c -g test.c: In function ‘main’: test.c:12: warning: passing argument 1 of ‘foo’ from incompatible pointer type test.c:13: warning: comparison of distinct pointer types lacks a cast $ ./a.out Both pointers are the same Both pointers are the same Can anyone explain why they are not different? I suspect it is because I cannot get the address of an array (as I cannot have & &x), but in this case the code should not compile.

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  • PHP: Need a double check on an error in this small code

    - by Josh K
    I have this simple Select box that is suppose to store the selected value in a hidden input, which can then be used for POST (I am doing it this way to use data from disabled drop down menus) <body> <?php $Z = $_POST[hdn]; ?> <form id="form1" name="form1" method="post" action="test.php"> <select name="whatever" id="whatever" onchange="document.getElementById('hdn').value = this.value"> <option value="1">1Value</option> <option value="2">2Value</option> <option value="3">3Value</option> <option value="4">4Value</option> </select> <input type="hidden" name ='hdn' id="hdn" /> <input type="submit" id='submit' /> <?php echo "<p>".$Z."</p>"; ?> </form> </body> The echo call works for the last 3 options (2,3,4) but if I select the first one it doesnt output anything, and even if i change first one it still doesnt output anything. Can someone explain to me whats going on, I think it might be a syntax issue.

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  • How to gracefully handle YouTube thumbnail broken images when videos are taken down?

    - by mrjf
    Our site contains some lists of YouTube videos with their thumbnails linked to the movies themselves. We fetch the thumbnail URLs from the YouTube API, and hotlink to them in situ on YouTube's servers. So our image tags look like: <img src="http://i.ytimg.com/vi/o6CHqSN7O-o/2.jpg" alt="" width="133" height="78" /> The problem is that sometimes a video gets removed -- and so does the thumbnail. We don't know when that might happen, and our thumbnails just turn into broken images. How can we handle this? There are a number of solutions: Download thumbnails and store them locally -- movie won't work, but that's ok, it will explain it was removed, and we avoid the broken image Check periodically with the API to see if the image thumbnail has changed -- if it no longer exists, substitute our own "movie removed" thumbnail. This is pretty heavy on the API calling! Use JavaScript to replace broken images (don't like this one much) Our ideal solution would be to point the img src to a location on YouTube that would display a friendly "move removed" image when a movie goes down. However, that doesn't seem to exist. Anyone else dealt with this? Thanks!

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  • how to fetch data using jquery

    - by user3566029
    I have tried to connect my index.php file in 000webhost.com using jQuery. From the site menu I have connected with 000webhost using FTP details available in 000webhost.com. When I tried to read data from jQuery it doesn’t working. Anyone please tell me what should I need to change? Should I need to connect my Dreamweaver database to webhost? If yes please explain? This is what I have done. index.php $mysql_host = "mysql0.000webhost.com"; $mysql_database = "a000000_mydb"; $mysql_user = "a000000_root"; $mysql_password = "******"; $conn=@mysql_connect ( $mysql_host,$mysql_user,$mysql_password )or die('aa'); mysql_select_db($mysql_database,$conn) or die('eoor on db'); $quer=mysql_query("SELECT * FROM sam"); $res=array(); while($row=mysql_fetch_row($quer)) { $res[]=$row; } print(json_encode($res)); return json_encode($res); mysql_close(); index.html $.get('public_html/index.php', function( data ) { alert( 'Successful' +data); });

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  • Sheet and thread memory problem

    - by Xident
    Hi Guys, recently I started a project which can export some precalculated Grafix/Audio to files, for after processing. All I was doing is to put a new Window (with progressindicator and an Abort Button) in my main xib and opened it using the following code: [NSApp beginSheet: REC_Sheet modalForWindow: MOTHER_WINDOW modalDelegate: self didEndSelector: nil contextInfo: nil]; NSModalSession session=[NSApp beginModalSessionForWindow:REC_Sheet]; RECISNOTDONE=YES; while (RECISNOTDONE) { if ([NSApp runModalSession:session]!=NSRunContinuesResponse) break; usleep(100); } [NSApp endModalSession:session]; A Background Thread (pthread) was started earlier, to actually perform the work and save all the targas/wave file. Which worked great, but after an amount of time, it turned out that the main thread was not responding anymore and my memory footprint raised unstoppable. I tried to debug it with Instruments, and saw a lot of CFHash etc stuff growing to infinity. By accident i clicked below the sheet, and temporary it helped, the main thread (AppKit ?) was releasing it's stuff, but just for a little time. I can't explain it to me, first of all I thought it was the access from my thread to the Progressbar to update the Progress (intervalled at 0,5sec), so I cut it out. But even if I'm not updating anything and did nothing with the Progressbar, my Application eat up all the Memory, because of not releasing it's "Main-Event" or whatsoever Stuff. Is there any possibility to "drain" this Main thread Memory stuff (Runloop / NSApp call?). And why the heck doesn't the Main thread respond anymore (after this simple task) ??? I don't have a clou anymore, please help ! Thanks in advance ! P.S. How do you guys implement "threaded long task" Stuff and updating your gui ???

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  • PHP: Adding arrays together

    - by Svish
    Could someone help me explain this? I have two snippets of code, one works as I expect, but the other does not. This works $a = array('a' => 1, 'b' => 2); $b = array('c' => 3); $c = $a + $b; print_r($c); // Output Array ( [a] => 1 [b] => 2 [c] => 3 ) This does not $a = array('a', 'b'); $b = array('c'); $c = $a + $b; print_r($c); // Output Array ( [a] => 1 [b] => 2 ) What is going on here?? Why doesn't the second version also add the two arrays together? What have I misunderstood? What should I be doing instead? Or is it a bug in PHP?

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  • Speeding up a group by date query on a big table in postgres

    - by zaius
    I've got a table with around 20 million rows. For arguments sake, lets say there are two columns in the table - an id and a timestamp. I'm trying to get a count of the number of items per day. Here's what I have at the moment. SELECT DATE(timestamp) AS day, COUNT(*) FROM actions WHERE DATE(timestamp) >= '20100101' AND DATE(timestamp) < '20110101' GROUP BY day; Without any indices, this takes about a 30s to run on my machine. Here's the explain analyze output: GroupAggregate (cost=675462.78..676813.42 rows=46532 width=8) (actual time=24467.404..32417.643 rows=346 loops=1) -> Sort (cost=675462.78..675680.34 rows=87021 width=8) (actual time=24466.730..29071.438 rows=17321121 loops=1) Sort Key: (date("timestamp")) Sort Method: external merge Disk: 372496kB -> Seq Scan on actions (cost=0.00..667133.11 rows=87021 width=8) (actual time=1.981..12368.186 rows=17321121 loops=1) Filter: ((date("timestamp") >= '2010-01-01'::date) AND (date("timestamp") < '2011-01-01'::date)) Total runtime: 32447.762 ms Since I'm seeing a sequential scan, I tried to index on the date aggregate CREATE INDEX ON actions (DATE(timestamp)); Which cuts the speed by about 50%. HashAggregate (cost=796710.64..796716.19 rows=370 width=8) (actual time=17038.503..17038.590 rows=346 loops=1) -> Seq Scan on actions (cost=0.00..710202.27 rows=17301674 width=8) (actual time=1.745..12080.877 rows=17321121 loops=1) Filter: ((date("timestamp") >= '2010-01-01'::date) AND (date("timestamp") < '2011-01-01'::date)) Total runtime: 17038.663 ms I'm new to this whole query-optimization business, and I have no idea what to do next. Any clues how I could get this query running faster?

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  • Array Assignment

    - by Mahesh
    Let me explain with an example - #include <iostream> void foo( int a[2], int b[2] ) // I understand that, compiler doesn't bother about the // array index and converts them to int *a, int *b { a = b ; // At this point, how ever assignment operation is valid. } int main() { int a[] = { 1,2 }; int b[] = { 3,4 }; foo( a, b ); a = b; // Why is this invalid here. return 0; } Is it because, array decays to a pointer when passed to a function foo(..), assignment operation is possible. And in main, is it because they are of type int[] which invalidates the assignment operation. Doesn't a,b in both the cases mean the same ? Thanks. Edit 1: When I do it in a function foo, it's assigning the b's starting element location to a. So, thinking in terms of it, what made the language developers not do the same in main(). Want to know the reason.

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  • TFS merging for users that are used to VSS

    - by JacksonD
    I just migrated a team of 7 developers from VSS to TFS. I migrated all of their code into a DEV folder which I then branched into a QA folder (which I branched into a PROD folder). The developers usually don't work on the same files, but there are some shared utility classes. All of the code is for a large ASP.NET web site. When the developers are ready to merge from DEV to QA, they only want to merge their changes. For example, let's say that Developer1 has been working on a project for the last 3 months and he's ready to merge all of his code into QA. However, Developer2 has been working on a different project for the last 2 months which is not ready to be merged. Developer1 and Developer2's changes are not in any way dependent on each other, but they are not separated into different folder structures and they each regularly do a get latest. There doesn't seem to be a way for developer1 to only merge his changes without also merging all of developer2's changes. Currently, developer1 is going through the Pending Changes window and 'Undoing Pending Changes' for all of Developer2's changes, but this is time consuming. They could merge each file individually, but this is also time consuming. Is there an easier way? I am going to have a coronary if I hear one more person explain how much easier it was to work in VSS.

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  • Is there a selector or a work around to select any element with no children.

    - by rnaud
    Looking at the CSS3 specs, I can't find any way to select any element that has no children. Let me explain. <body> <h1>Main Page</h1> <div id="main"> <div class="post"> <h2>Article 1</h1> <p>some text</p> </div> <div class="post"> <h2>Article 2</h1> <p>some text</p> </div> </div> </body> I'm looking for a CSS syntax to select the h1, the two h2 and the two p. A way to select in any page, all elements with no children. Any suggestion ? Sorry, I forgot to add the "empty" part, I am actually already using the *:empty selector, but it's not working for any tag that has a nodeText as a child. So it's working for any input, image, object, but not for h2, h1, or any p.

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  • Checking Selected Radio Button after POST

    - by coffeeaddict
    I've been using ASP.NET controls which perform a lot of the manual for you. But I'm going back to the basics, what everyone else does. I'm using standard input tags. So for example if I have a radio button group and I select a button. When the form submits and does a POST back to whatever action="MyPage.aspx" then to grab and check the radio button's value that was selected is it always done like this below? <label><input type="radio" name="rbGroup" value='<%# ((Action)Container.DataItem).ID %>'/><%# ((Action)Container.DataItem).Name %></label> So here I'm appending the ID to the value. And then when it hits the page that my action specifies, I'm checking to see which was selected by trimming off and getting that ID from the value: string selection = Request.Form["rbGroup"]; string dbRecordIdSelected = int.Parse(selection.Substring(1)); so now I can check the id they selected...that is the ID of the db record that gave that selected radio it's name. Is that how you basically always check what radio was selected by checking the name/value pair that comes across for that selected radioButton group name? And then you can append stuff like IDs or whatever you want to grab and parse out to then do additional logic on the server-side once that header reaches the server and your specified page in the action attribute? The above code is not production code, just something to explain what I'm talking about.

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  • Why doesn't Firefox redownload images already on a page?

    - by vvo
    Hello, i just read this article : https://developer.mozilla.org/en/HTTP_Caching_FAQ There's a firefox behavior (and some other browsers i guess) i'd like to understand : if i take any webpage and try to insert the same image multiple times in javascript, the image is only downloaded ONCE even if i specifiy all needed headers to say "do no ever use cache". (see article) I know there are workarounds (like addind query strings to end of urls etc) but why do firefox act like that, if i say that an image do not have to be cached, why is the image still taken from cache when i try to re-insert it ? Plus, what cache is used for this ? (I guess it's the memory cache) Is this behavior the same for dynamic inclusion for example ? ANSWSER IS NO :) I just tested it and the same headers for a js script will make firefox redownload it each time you append the script to the DOM. PS: I know you're wondering WHY i need to do that (appending same image multiple times and force to redownload but this is the way our app works) thank you The good answer is : firefox will store images for the current page load in the memory cache even if you specify he doesnt have to cache them. You can't change this behavior but this is odd because it's not the same for javascript files for example Could someone explain or link to a document describing how firefox cache WORKS?

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  • Getting rid of function's argument

    - by Max
    It is better to explain my intention with code. So right now I have the following code: class A, IInterfaceUsedByB { } class B { void func(A someObject) { func2(someObject, 1); func3(someObject, "string"); func4(someObject, new MyObject()); } func2(A someObject, int val); func3(A someObject, string val); func4(A someObject, C val); } Where func2, func3, func4 do need references to someObject. I want to change this to void func() { with(someObject, () => { func2(1); func3("string"); func4(new MyObject()); } ); } Or even better to void func(someObject) { func2(1); func3("string"); func4(new MyObject()); } So that I don't have to drag this someObject around, but I should still be able to use it inside func2,3,4. I can use any of the three languages (C#, F# or IronPython) for this. UPDATE In the ideal solution class B would be independent of A. func* functions only depend on a small interface of A consisting of 2 methods.

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  • Strange behavior when overloading methods in Java

    - by Sep
    I came across this weird (in my opinion) behavior today. Take this simple Test class: public class Test { public static void main(String[] args) { Test t = new Test(); t.run(); } private void run() { List<Object> list = new ArrayList<Object>(); list.add(new Object()); list.add(new Object()); method(list); } public void method(Object o) { System.out.println("Object"); } public void method(List<Object> o) { System.out.println("List of Objects"); } } It behaves the way you expect, printing "List of Objects". But if you change the following three lines: List<String> list = new ArrayList<String>(); list.add(""); list.add(""); you will get "Object" instead. I tried this a few other ways and got the same result. Is this a bug or is it a normal behavior? And if it is normal, can someone explain why? Thanks.

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  • WPF problem modify style of images in multiple Button Templates

    - by user556415
    I'm trying to create a control panel for a video camera, the panel has buttons for up, down, left and right etc. Each camera function up, down, left and right is represented by three images (see code below) for the left side, middle and right side. The control panel is circular so the corner images kind of overlap (its complicated to explain this without a visual). When I click on up for example I have to hide the initial three images (leftside, middle and right side) and display another three images for left , middle and right that indicate that the button is pressed. I am achieving this by having a grid inside a button template. The problem I have is that for the corner images for the control there are really four images that represent this. For example for the top left corner the four images would be represent 1. Top not clicked. 2. Top Clicked and 3. Left Not clicked and 4. Left Clicked. My problem is if I need to make the images contained within the Top button have precedence when the top control is clicked or the images in the left button have precedence when the left button is clicked. So it's like I want to modify the left button's image visible property when the top button is clicked and vise versa. This is really difficult to explain so I apologize if it makes little sense but I can email the source code on request if anyone is interested in my predicament. <Grid> <Canvas> <!--<StackPanel>--> <Button Name="TopSide" xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation" Height="34" Width="102" Canvas.Left="97" Canvas.Top="60" xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml" > <Button.Template> <ControlTemplate TargetType="{x:Type Button}"> <Grid Width="100"> <Canvas> <Image Name="TopRightNormal" Source="Resources/topright_off.jpg" Height="34" Width="34" Canvas.Left="66"></Image> <Image Name="TopRightDown" Source="Resources/topright_down.jpg" Height="34" Width="34" Canvas.Left="66" Visibility="Hidden" ></Image> <Image Name="TopNormal" Source="Resources/topcenter_off.jpg" Height="34" Width="34" Canvas.Left="34" /> <Image Name="TopPressed" Source="Resources/topcenter_down.jpg" Height="34" Width="34" Canvas.Left="34" Visibility="Hidden" /> <Image Name="TopDisabled" Source="Resources/topcenter_off.jpg" Height="34" Width="34" Canvas.Left="34" Visibility="Hidden" /> <Image Name="TopLeftNormal" Source="Resources/topleft_off.jpg" Height="34" Width="34" Canvas.Left="2" ></Image> <Image Name="TopLeftDown" Opacity="0" Source="Resources/topleft_down.jpg" Height="34" Width="34" Canvas.Left="2" Visibility="Hidden" ></Image> </Canvas> </Grid> <ControlTemplate.Triggers> <Trigger Property="IsPressed" Value="True"> <Setter TargetName="TopNormal" Property="Visibility" Value="Hidden" /> <Setter TargetName="TopPressed" Property="Visibility" Value="Visible" /> <Setter TargetName="TopRightNormal" Property="Visibility" Value="Hidden" /> <Setter TargetName="TopRightDown" Property="Visibility" Value="Visible" /> <Setter TargetName="TopLeftNormal" Property="Visibility" Value="Hidden" /> <Setter TargetName="TopLeftDown" Property="Visibility" Value="Visible" /> <Setter TargetName="TopLeftDown" Property="Opacity" Value="100" /> </Trigger> <Trigger Property="IsEnabled" Value="False"> <Setter TargetName="TopNormal" Property="Visibility" Value="Hidden" /> <Setter TargetName="TopDisabled" Property="Visibility" Value="Visible" /> </Trigger> </ControlTemplate.Triggers> </ControlTemplate> </Button.Template> </Button> <!--</StackPanel>--> <!--<StackPanel>--> <Button Name="LeftSide" xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation" Canvas.Left="100" Canvas.Top="60" xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml" MouseDown="Button_MouseDown_1"> <Button.Template> <ControlTemplate TargetType="{x:Type Button}"> <Grid Width="34" Height="100"> <Canvas> <Image Name="TopLeftNormal" Source="Resources/topleft_off.jpg" Height="34" Width="34" Canvas.Left="0"></Image> <Image Name="TopLeftDown" Opacity="0" Source="Resources/topleft_leftdown.jpg" Height="34" Width="34" Canvas.Left="0" Visibility="Hidden" ></Image> <Image Name="Normal" Source="Resources/leftcenter_off.jpg" Height="34" Width="34" Canvas.Top="32" Canvas.Left="0"/> <Image Name="Pressed" Source="Resources/leftcenter_down.jpg" Visibility="Hidden" Canvas.Top="32" Height="34" Width="34" /> <Image Name="Disabled" Source="Resources/leftcenter_off.jpg" Visibility="Hidden" Height="34" Width="34" Canvas.Top="32" /> </Canvas> </Grid> <ControlTemplate.Triggers> <Trigger Property="IsPressed" Value="True"> <Setter TargetName="Normal" Property="Visibility" Value="Hidden" /> <Setter TargetName="Pressed" Property="Visibility" Value="Visible" /> <Setter TargetName="TopLeftNormal" Property="Visibility" Value="Hidden" /> <Setter TargetName="TopLeftNormal" Property="Opacity" Value="0" /> <Setter TargetName="TopLeftDown" Property="Visibility" Value="Visible" /> <Setter TargetName="TopLeftDown" Property="Opacity" Value="100" /> </Trigger> <Trigger Property="IsEnabled" Value="False"> <Setter TargetName="Normal" Property="Visibility" Value="Hidden" /> <Setter TargetName="Disabled" Property="Visibility" Value="Visible" /> </Trigger> </ControlTemplate.Triggers> </ControlTemplate> </Button.Template> </Button> <!--</StackPanel>--> <!--<StackPanel>--> <Button xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation" Height="34" Width="34" Canvas.Left="165" Canvas.Top="92" xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml" MouseDown="Button_MouseDown_2" > <Button.Template> <ControlTemplate TargetType="{x:Type Button}"> <Grid> <Image Name="Normal" Source="Resources/rightcenter_off.jpg" /> <Image Name="Pressed" Source="Resources/rightcenter_down.jpg" Visibility="Hidden" /> <Image Name="Disabled" Source="Resources/rightcenter_off.jpg" Visibility="Hidden" /> </Grid> <ControlTemplate.Triggers> <Trigger Property="IsPressed" Value="True"> <Setter TargetName="Normal" Property="Visibility" Value="Hidden" /> <Setter TargetName="Pressed" Property="Visibility" Value="Visible" /> </Trigger> <Trigger Property="IsEnabled" Value="False"> <Setter TargetName="Normal" Property="Visibility" Value="Hidden" /> <Setter TargetName="Disabled" Property="Visibility" Value="Visible" /> </Trigger> </ControlTemplate.Triggers> </ControlTemplate> </Button.Template> </Button> <!--</StackPanel>--> <!--<StackPanel>--> <Button xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation" Height="34" Width="34" Canvas.Left="133" Canvas.Top="124" xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml" > <Button.Template> <ControlTemplate TargetType="{x:Type Button}"> <Grid> <Image Name="BottomNormal" Source="Resources/bottomcenter_off.jpg" /> <Image Name="BottomPressed" Source="Resources/bottomcenter_down.jpg" Visibility="Hidden" /> <Image Name="BottomDisabled" Source="Resources/bottomcenter_off.jpg" Visibility="Hidden" /> </Grid> <ControlTemplate.Triggers> <Trigger Property="IsPressed" Value="True"> <Setter TargetName="BottomNormal" Property="Visibility" Value="Hidden" /> <Setter TargetName="BottomPressed" Property="Visibility" Value="Visible" /> </Trigger> <Trigger Property="IsEnabled" Value="False"> <Setter TargetName="BottomNormal" Property="Visibility" Value="Hidden" /> <Setter TargetName="BottomDisabled" Property="Visibility" Value="Visible" /> </Trigger> </ControlTemplate.Triggers> </ControlTemplate> </Button.Template> </Button> <!--</StackPanel>--> <Image Source="Resources/bottomright_off.jpg" Height="34" Width="34" Canvas.Left="165" Canvas.Top="124"></Image> <Image Source="Resources/bottomleft_off.jpg" Height="34" Width="34" Canvas.Left="100" Canvas.Top="124"></Image> <!--<ToggleButton Style="{StaticResource MyToggleButtonStyle}" Height="34" Width="34" Margin="150,100"/>--> </Canvas> </Grid>

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  • please help me to solve problem

    - by davit-datuashvili
    first of all this is not homework and nobody tag it as homewrok i did not understand this porblem can anybody explain me?this is not english problem it is just misunderstanding what problem say Consider the problem of neatly printing a paragraph on a printer. The input text is a sequence of n words of lengths l1 , l2 , . . . , ln , measured in characters. We want to print this paragraph neatly on a number of lines that hold a maximum of M characters each. Our criterion of “neatness” is as follows. If a given line contains words i through j , where i = j , and we leave exactly one space between words, the number of extra space characters at the end of the line is M - j + i -(k=i,k< j,k++) lk , which must be nonnegative so that the words fit on the line. We wish to minimize the sum, over all lines except the last, of the cubes of the numbers of extra space characters at the ends of lines. Give a dynamic-programming algorithm to print a paragraph of n words neatly on a printer. Analyze the running time and space requirements of your algorithm.

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  • Big-Oh running time of code in Java (are my answers accurate

    - by Terry Frederick
    the Method hasTwoTrueValues returns true if at least two values in an array of booleans are true. Provide the Big-Oh running time for all three implementations proposed. // Version 1 public boolean has TwoTrueValues( boolean [ ] arr ) { int count = 0; for( int i = 0; i < arr. length; i++ ) if( arr[ i ] ) count++; return count >= 2; } // Version 2 public boolean hasTwoTrueValues( boolean [ ] arr ) { for( int i = 0; i < arr.length; i++ ) for( int j = i + 1; j < arr.length; j++ ) if( arr[ i ] && arr[ j ] ) return true; } // Version 3 public boolean hasTwoTrueValues( boolean [ ] arr ) { for( int i = 0; i < arr.length; i++ if( arr[ i ] ) for( int j = i + 1; j < arr.length; j++ ) if( arr[ j ] ) return true; return false; } For Version 1 I say the running time is O(n) Version 2 I say O(n^2) Version 3 I say O(n^2) I am really new to this Big Oh Notation so if my answers are incorrect could you please explain and help.

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  • C++: how serialize/deserialize objects without any library?

    - by Winte Winte
    I try to understand how serializing/deserializing works in c++, so I want to do that without any libs. But I really stuck with that. I start with simple objects but when I try to deserilize a vector I understand that I can't get a vector without if I don't write it size before. Moreover, I don't know which format of file I should choose because if digits will be existed before size of vector I haven't chance to read it right. However it is only the vector but I also want to do that with classes and map container. My task is serialize/deserialize a objects as this: PersonInfo { unsigned int age_; string name_; enum { undef, man, woman } sex_; } Person : PersonInfo { vector<Person> children_; map<string, PersonInfo> addrBook_; } Currently I know how to serialize simple objects in way as this: vector<PersonInfo> vecPersonInfo; vecPersonInfo.push_back(*personInfo); vecPersonInfo.push_back(*oneMorePersonInfo); ofstream file("file", ios::out | ios::binary); if (!file) { cout<<"can not open file"; } else { vector<PersonInfo>::const_iterator iterator = vecPersonInfo.begin(); for (; iterator != vecPersonInfo.end(); iterator++) { file<<*iterator; } Could you please suggest how I can do this for this conplex object or a good tutorial that explain it clearly?

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  • jQuery .ready() automatically assigning variables for each element with ID in DOM

    - by Greg
    I have noticed some unexpected behaviour when using the jQuery .ready() function, whereby afterwards you can reference an element in the DOM simply by using its ID without prior declaration or assignment: <html> <script src="jquery.js"></script> <script> $(document).ready(function() { myowndiv.innerHTML = 'wow!' }); </script> <body> <div id="myowndiv"></div> </body> </html> I would have expected to have to declare and assign myowndiv with document.getElementById("myowndiv"); or $("#myowndiv"); before I could call innerHTML or anything else on it? Is this behaviour by design? Can anyone explain why? My fear is that if I refactor and end up not using .ready() or even using jQuery at all then my code will fail to execute. Cheers!

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  • C++ STL 101: Overload function causes build error

    - by Sidjal
    Trivial code that works if I do not overload myfunc. void myfunc(int i) { std::cout << "calling myfunc with arg " << i << std::endl; } void myfunc(std::string s) { std::cout << "calling myfunc with arg " << s << std::endl; } void testalgos() { std::vector<int> v; v.push_back(1); v.push_back(2); std::vector<std::string> s; s.push_back("one"); s.push_back("two"); std::for_each( v.begin(), v.end(), myfunc); std::for_each( s.begin(), s.end(), myfunc); return; } int _tmain(int argc, _TCHAR* argv[]) { std::cout << "Hello World" << std::endl; testalgos(); return 0; } The following build errors repeat for both for_each calls. error C2914: 'std::for_each' : cannot deduce template argument as function argument is ambiguous error C2784: '_Fn1 std::for_each(_InIt,_InIt,_Fn1)' : could not deduce template argument for '_InIt' from 'std::_Vector_iterator<_Ty,_Alloc'. It does work if I do not overload myfunc.Can someone explain what is happening here. TIA

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  • Global State and Singletons Dependency injection

    - by Manu
    this is a problem i face lot of times when i am designing a new app i'll use a sample problem to explain this think i am writing simple game.so i want to hold a list of players. i have few options.. 1.use a static field in some class private static ArrayList<Player> players = new ArrayList<Integer>(); public Player getPlayer(int i){ return players.get(i); } but this a global state 2.or i can use a singleton class PlayerList{ private PlayerList instance; private PlayerList(){...} public PlayerList getInstance() { if(instance==null){ ... } return instance; } } but this is bad because it's a singleton 3.Dependency injection class Game { private PlayerList playerList; public Game(PlayerList list) { this.list = list; } public PlayerList getPlayerList() { return playerList; } } this seems good but it's not, if any object outside Game need to look at PlayerList (which is the usual case) i have to use one of the above methods to make the Game class available globally. so I just add another layer to the problem. didn't actually solve anything. what is the optimum solution ? (currently i use Singleton approach)

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  • c# Find value in a range using lambda

    - by n4rzul
    I'm trying to find an item in a list of values based on another value using a lambda expression using the Find method. In this example I'm expecting to get back -1000, but for the life of me, I just can't come up with the proper lamda expression. If that sounds confusing I hope the code and comments below explain it better. TIA. using System; using System.Collections.Generic; namespace TestingStuff { class Program { static void Main(string[] args) { double amount = -200; //The Range of values List<MyValue> values = new List<MyValue>(); values.Add(new MyValue(-1000)); values.Add(new MyValue(-100)); values.Add(new MyValue(-10)); values.Add(new MyValue(0)); values.Add(new MyValue(100)); values.Add(new MyValue(1000)); //Find it!!! MyValue fVal = values.Find(x => (x.Value > amount) && (x.Value < amount)); //Expecting -1000 as a result here since -200 falls between -1000 and -100 //if it were -90 I'd expect -100 since it falls between -100 and 0 if (fVal != null) Console.WriteLine(fVal.Value); Console.ReadKey(); } } public class MyValue { public double Value { get; set; } public MyValue(double value) { Value = value; } } }

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  • PHP array minor problem

    - by Sennheiser
    I'm really not sure how to explain this. It's so simple I can't fathom why it's not working. I have a loop. It puts a bunch of strings into an array. If I fill a single variable with any given string, it will output it perfectly. But filling an array with the strings will make it give me the dreaded: Array Array Array Array Array Array Array Array Note: my strings are not all 'Array'. The way I loop is: while(...) { $arr[] = $resultFromLoop; } Here is my var_dump. array(1) { ["tagName"]=> string(5) "magic" } array(1) { ["tagName"]=> string(4) "nunu" } array(1) { ["tagName"]=> string(5) "books" } array(1) { ["tagName"]=> string(0) "" } array(1) { ["tagName"]=> string(3) "zzz" } array(1) { ["tagName"]=> string(4) "grey" } array(1) { ["tagName"]=> string(3) "new" } array(1) { ["tagName"]=> string(6) "flight" }

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  • an error "has no member named"

    - by helloWorld
    I have this snippet of the code account.cpp #include "account.h" #include <iostream> #include <string> using namespace std; Account::Account(string firstName, string lastName, int id) : strFirstName(firstName), strLastName(lastName), nID(id) {} void Account::printAccount(){ cout << strFirstName; } account.h #include <string> using std::string; class Account{ private: string strLastName; //Client's last name string strFirstName; //Client's first name int nID; //Client's ID number int nLines; //Number of lines related to account double lastBill; public: Account(string firstName, string lastName, int id); void printAccount(); }; company.h #ifndef CELLULAR_COMPANY_H #define CELLULAR_COMPANY_H #include <string> #include <list> #include <iostream> #include "account.h" using namespace std; class Company { private: list<Account> listOfAccounts; public: void addAccount(string firstName, string lastName, int id) { Account newAccount(firstName, lastName, id); listOfAccounts.push_back(newAccount); } void printAccounts(){ for(list<Account>::iterator i = listOfAccounts.begin(); i != listOfAccounts.end(); ++i){ i.printAccount; //here bug } } }; #endif // CELLULAR_COMPANY_H main.cpp #include "cellularcompany.h" int main(){ Company newCompany; newCompany.addAccount("Pavel", "Nedved", 11111); newCompany.printAccounts(); return 0; } can somebody please explain what does my error mean? thanks in advance (I have it in company.h see comment there) I have bug 'struct std::_List_iterator<Account>' has no member named 'printAccount'

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  • Memcached getDelayed alternative implementation

    - by iBobo
    I would like to use getDelayed on the PHP Memcached extension but I think it's not implemented in the right way. Right now you ask for some keys and then retrieve all of them with fetch() and fetchAll(). But imagine a scenario where I need to retrieve 15 keys used in different parts of the page which I don't know in advance, but I can ask the various objects to give me the list. What I want is give the Memcached instance this list (each component would give its part) then later when I need them retrieve from the instance, but not all of them at once: each component would take the one it needs. Basically if I were to implement this I would prohibit using getDelayed alone and implement a bookGet($keys) method where you would add the keys to book (which actually calls getDelayed), and redefine get to handle these three cases: key is booked and retrieved - return the value; key is booked but not retrieved - go and force the fetch of the booked keys and return the correct value; key not booked - do a normal lookup. I want to know if this makes sense, your thoughts on the subject and if someone already implemented this or maybe PECL Memcached already works this way and actually the documentation doesn't explain it correctly.

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