Search Results

Search found 9047 results on 362 pages for 'double math'.

Page 276/362 | < Previous Page | 272 273 274 275 276 277 278 279 280 281 282 283  | Next Page >

  • Can I use a single pointer for my hash table in C?

    - by aks
    I want to implement a hash table in the following manner: struct list { char *string; struct list *next; }; struct hash_table { int size; /* the size of the table */ struct list **table; /* the table elements */ }; Instead of struct hash_table like above, can I use: struct hash_table { int size; /* the size of the table */ struct list *table; /* the table elements */ }; That is, can I just use a single pointer instead of a double pointer for the hash table elements? If yes, please explain the difference in the way the elements will be stored in the table?

    Read the article

  • Array as struct database?

    - by user2985179
    I have a struct that reads data from the user: typedef struct { int seconds; } Time; typedef struct { Time time; double distance; } Training; Training input; scanf("%d %lf", input.time.seconds, input.distance); This scanf will be looped and the user can input different data every time, I want to store this data in an array for later use. I THINK I want something like arr[0].seconds and arr[0].distance. I tried to store the entered data in an array but it didn't really work at all... Training data[10]; data[10].seconds = input.time.seconds; data[10].distance = input.distance; The data will wipe when the program closes and that's how I like it to be. So I want it to be stored in an array, no files or databases!

    Read the article

  • QFileDialog used as widget

    - by lvp
    Hi! My goal is: user can choose file (only *mp3) and after clicking twice on it it should play (so the QString to file should be send to play() funtion) Firstly I started to work with QTreeView, but it has signal when the file is selected. So I decided to create QFileDialog and used it as widget built-in into MainWindow. The only problem that I have, that after double-click it dissapers. It is possible to avoid it? Should I work with some QDialog::finished() signal or, QDialog::done()?

    Read the article

  • EF Linq Product Sum when no records returned

    - by user1622713
    I’ve seen variations of this question all over the place but none of the answers work for me. Most of them are just trying to sum a single column too – nothing more complex such as the sum of a product as below: public double Total { get { return _Context.Sales.Where(t => t.Quantity > 0) .DefaultIfEmpty() .Sum(t => t.Quantity * t.Price); } } If no rows are returned I want to return zero. However if no rows are returned the .Sum() fails. There are various options of trying to insert Convert.ToDouble and using null coalesce operators, but they all still gave me errors. I’m sure I am missing a simple way to do this – any help greatly appreciated after too long banging head against google brick wall!

    Read the article

  • MySQL query with JOINS and GROUP BY

    - by user1854049
    I'm building a MySQL query but I can't seem to get it right. I have four tables: - customers - orders - sales_rates - purchase_rates There is a 1:n relation 'customernr' between customers and orders. There is a 1:n relation 'ordernr' between orders and sales_rates. There is a 1:n relation 'ordernr' between orders and purchase_rates. What I would like to do is produce an output of all customers with their total purchase and sales amounts. So far I have the following query. SELECT c.customernr, c.customer_name, SUM(sr.sales_price) AS sales_price, SUM(pr.purchase_price) AS purchase_price FROM orders o, customers c, sales_rates sr, purchase_rates pr WHERE o.customernr = c.customernr AND o.ordernr = sr.ordernr AND o.ordernr = pr.ordernr GROUP BY k.bedrijfsnaam The result of the sales_price and purchase_price is far too high. I seem to be getting double counts. What am I doing wrong? Is it possible to perform this in a single query? Thank for your response!

    Read the article

  • Data-binding taking too long to update

    - by Justin
    In my application I have this code in my view model: hiddenTextContainer.PreHideVerticalOffset = VerticalOffset; hiddenTextContainer.HiddenText = Text.Remove(SelectionStart, SelectionLength); hiddenTextContainer.HasHiddenText = true; hiddenTextContainer.NonHiddenTextStart = SelectionStart; Text = Text.Substring(SelectionStart, SelectionLength); SelectionStart = Text.Length; hiddenTextContainer.ImmediatePostHideVerticalOffset = VerticalOffset; This code is used to hide selected text in a textbox. Text is a string property data bound to the text property of a textbox and VerticalOffset is a double property data bound to the VerticalOffset property of that same textbox. I need to save the VerticalOffset before and after the hiding of selected text takes place, but with my code below both hiddenTextContainer.PreHideVerticalOffset and hiddenTextContainer.ImmediatePostHideVerticalOffset are always set to the same value no matter what. I have figured out that this is because the text of the textbox has not been updated by the time the code reaches: hiddenTextContainer.ImmediatePostHideVerticalOffset = VerticalOffset; Is there any way I can fix this?

    Read the article

  • Force type of C++ template

    - by gregseth
    Hi, I've a basic template class, but I'd like to restrain the type of the specialisation to a set of classes or types. e.g.: template <typename T> class MyClass { .../... private: T* _p; }; MyClass<std::string> a; // OK MYCLass<short> b; // OK MyClass<double> c; // not OK Those are just examples, the allowed types may vary. Is that even possible? If it is, how to do so? Thanks.

    Read the article

  • RSpec "undefined local variable or method `user'"

    - by Justin
    I have the following test written in RSpec: describe '#create' do ... it 'redirects users to profile page' do response.should redirect_to user_path(user) end ... ... And the following in my UsersController: def create @user = User.new(params[:user]) if @user.save redirect_to user_path(@user) end end Does anyone know why this is returning the following error: NameError: undefined local variable or method 'user' I also tried changing this to be root_url in both cases instead of user_path(user) and it gave a different error saying: Expected response to be a <:redirect>, but was <200> Does anyone know what the issue might be? I have double-checked my code and have seen similar questions posted online, but haven't been able to find a solution. Thanks in advance for any help!

    Read the article

  • Any efficient way to read datas from large binary file?

    - by limi
    Hi, I need to handle tens of Gigabytes data in one binary file. Each record in the data file is variable length. So the file is like: <len1><data1><len2><data2>..........<lenN><dataN> The data contains integer, pointer, double value and so on. I found python can not even handle this situation. There is no problem if I read the whole file in memory. It's fast. But it seems the struct package is not good at performance. It almost stuck on unpack the bytes. Any help is appreciated. Thanks.

    Read the article

  • What is the purpose of AnyVal?

    - by DaoWen
    I can't think of any situation where the type AnyVal would be useful, especially with the addition of the Numeric type for abstracting over Int, Long, etc. Are there any actual use cases for AnyVal, or is it just an artifact that makes the type hierarchy a bit prettier? Just to clarify, I know what AnyVal is, I just can't think of any time that I would actually need it in Scala. When would I ever need a type that encompassed Int, Character and Double? It seems like it's just there to make the type hierarchy prettier (i.e. it looks nicer to have AnyVal and AnyRef as siblings rather than having Int, Character, etc. inherit directly from Any).

    Read the article

  • base pointer to derived class

    - by Jay
    Suppose there are Base class and Derived class. Base *A = new Base; Here A is a pointer point to Base class, and new constructs one that A points to. I also saw Base *B = new Derived; How to explain this? B is a pointer to Base Class, and a Derived class constructed and pointed by B? If there is a function derived from Base class, say, Virtual void f(), and it's been overridden in Derived class, then B->f() will invoke which version of the function? version in Base class, or version that overridden in Derived Class. What if there is a new function void g()in Derived, is B->g() going to invoke this function properly? One more is, is int *a = new double; or int *a = new int; legal?

    Read the article

  • bash screen title usage (screen -t "something")

    - by atrioom
    I was working with screen lately and wanted to use the -t option for it. What's the point of the-t option if the title of the screen does not show anywhere like when using -list or within the screen when it's attached? There is a command CTRL-A double-quote(") to see all active screens, and then it shows the title, but that does not really do the job, because I have to have the screen attached already. I want to read out the title BEFORE attaching any screens, to attach the right one in the first place. Is there a method to use -t in a convenient way? Edit: There is one method: "ctrl-a "" and then "ctrl-a {numberofscreen}". I guess that's the best way to use the screen titles?

    Read the article

  • Stringly typed values table in sql, is there a better way to do this? (we're using MSSQL)

    - by Jason Hernandez
    We have have a table layout with property names in one table, and values in a second table, and items in a third. (Yes, we're re-implementing tables in SQL.) We join all three to get a value of a property for a specific item. Unfortunately the values can have multiple data types double, varchar, bit, etc. Currently the consensus is to stringly type all the values and store the type name in the column next to the value. tblValues DataTypeName nvarchar Is there a better, cleaner way to do this?

    Read the article

  • In .NET, how can I convert from "0.000" to a 'long'?

    - by willem
    I have a string, "0.000" (or any similar string), that I would like to convert to a long. I am happy to "chop-off" anything after the decimal. What is the best way to go about this? I can convert to double and then to long, but I'm just wondering if there is an easier way. All the following statements throw exceptions: long l3 = Convert.ToInt64(nrToConvert); long l1; long.TryParse(nrToConvert, out l1); long l2 = long.Parse(nrToConvert);

    Read the article

  • How to tell the difference between a VBscript is run from command line or by clicking it in a window?

    - by robbie
    All I want to do is differentiate between the program being run by the command line or by clicking the test.vbs file in a window. If you run the script by typing C:\testFolder\test.vbs in a command prompt, then I want the program to run differently than if you double clicked test.vbs in the testFolder. Is there some system variable that I can use to differentiate between the two scenarios? I first attempted to use WScript.Fullname to determine if the pathname ended in cscript or wscript. But that didn't work so well. Any ideas are greatly appreciated.

    Read the article

  • Calculate average in LINQ C# with string representation of property name

    - by Paul
    I need to calculate a whole bunch of averages on an List of Surveys. The surveys have lots of properties that are int and double valued. I am creating a business object to handle all the calculations (there are like 100) and I'd rather not code 100 different methods for finding the average for a particular property. I'd like to be able to have the UI pass a string (representing the property) and have the the business object return an average for that property. So, like... int AverageHeightInInches = MyObject.GetIntAverage("HeightInInches"); . . . Then have linq code to calculate the result. Thanks!

    Read the article

  • How can I get the file extensions from relative links in HTML text using Perl?

    - by Structure
    For example, scanning the contents of an HTML page with a Perl regular expression, I want to match all file extensions but not TLD's in domain names. To do this I am making the assumption that all file extensions must be within double quotes. I came up with the following, and it is working, however, I am failing to figure out a way to exclude the TLDs in the domains. This will return "com", "net", etc. m/"[^<>]+\.([0-9A-Za-z]*)"/g Is it possible to negate the match if there is more than one period between the quotes that are separated by text? (ie: match foo.bar.com but not ./ or ../) Edit I am using $1 to return the value within parentheses.

    Read the article

  • STL ostream_iterator writes to screen even though I overwrote it?

    - by adam_0
    In my code, I have the following: ostream_iterator<double> doubleWriter(cout, " ~ "); // ... *doubleWriter = 1.1; doubleWriter++; *doubleWriter = 2.2; *doubleWriter = 3.3; // shouldn't 2.2 be overwritten? doubleWriter++; *doubleWriter = 44.2; cout << endl << endl; I expected it to output this: 1.1 ~ 3.3 ~ 44.2 ~ Instead, the output was this: 1.1 ~ 2.2 ~ 3.3 ~ 44.2 ~ Why does this happen? It would seem to me that I overwrite 2.2 and stick 3.3 in its spot, since I didn't increment. Is incrementation an optional step?

    Read the article

  • How do you get good line spacing with lpr?

    - by dan
    I'm using lpr with the following flags: lpr -o cpi=12 -o lpi=8 -o page-left=36 -o page-top=36 -o page-bottom=36 But the lines appear too close together. But if I decrease lpi to 6 or something, the font just gets taller. What I really want is control over the amount of space between the lines. My makeshift solution is to insert blank lines in the document using sed G, but ideally I would like to achieve 1.5 line spacing instead of full double-spaced. Is this possible?

    Read the article

  • JQuery input hidden bug

    - by Abude
    this is the code: Jsfiddle when you clear the url filed and leave it empty the input is hidden and disappear , need to return to the input tag wit h display if the value is empty by click or tab. i have a form with inputs the url input is edited by clicking on the link double click or click next to the link that means in the div area when it's done editing it converts the text to link the Problem: when you leave the input empty it make the attribute of the code and the input attribute hidden so no info is show neither can type an info. how can i make if that input with the id url0/url1 is empty to return to the input option to make it visible and can type?

    Read the article

  • how do i detect \r\n in a u_char type of buffer?

    - by aDi Adam
    i am trying to construct http content from packet sniffing in C. right now i am able to save all the packets in a file but i want to get rid of the headers in the first packet. they are also being saved as per they are a part of tcp payload. the actual body after the header starts after double "crlf" or \r\n\r\n in http response. how do i detect \r\n so that i can only save the following part of the buffer in the file. the buffer is u_char type. i cant figure out the command or the part i looked on google and other places but i mostly find c# commands, nothing in C.

    Read the article

  • How expensive is a call to java.util.HashMap.keySet()?

    - by fx42
    I implemented a sparse matrix as List<Map<Integer,Double>>. To get all entries of row i I call list.get(i).keySet(). How expensive is this call? I also used the trove library for an alternative implementation as List<TIntDoubleHashMap>. What's the cost of calling list.get(i).keys(), here? Do you have any further ideas of how to implement an efficient sparse matrix? Or can you provide a list of existing implementations in java?

    Read the article

  • WIndows file access control

    - by beezler
    I have a file on a Windows 2003 NTFS file system. It is called C:\MyFolder\MyFile.txt. First grant a user read access to the file. Then I remove the user's read access to the parent folder. Now the user cannot use Windows Explorer to browse the folder and double click to open in Notepad. The user can go to Start (menu) Run and enter "C:\MyFolder\MyFile.txt" and the file will load in Notepad. Can someone point me to some MSDN documentation that explains why this is? I've tried all the google and bing queries I can think of. thanks much

    Read the article

  • phpMySql connection

    - by Eiriko Pedroza
    PL = VB.net Issue: format of the initialization string does not conform to specification starting at index 17 connection string: objconn.ConnectionString = ("server=" & txtServer.Text & ";" _ & "user id=" & "'" & txtUserId.Text & ";" _ & "password=" & txtPassword.Text & ";" _ & "database=try") Try objconn.Open() MsgBox("Connected") objconn.Close() Catch ex As Exception MsgBox(ex.ToString) End Try -objconn is declared as new mysqlconnection every time I run the application and try to login, i keep on receiving this error message, I already double checked my line of connection string. im using 'localhost' as server and 'root' as username, password is blank. thank you in advance for your response

    Read the article

  • Similar Sub-Classes

    - by praks5432
    Lets say I have a class A that is fairly simple like this - public class A{ private int randomField = 0; protected int key; protected double dmg; } Now I want to write a number of sub-classes that inherit the protected fields and only differ based on the initial values that are assigned to those fields - for example, if I wrote two subclasses B and C, the only difference between those two sub-classes would be that the values key and dmg would have different values. They would share a method, set, which would be exactly the same, in that it would affect the same variable. I find when I'm writing these sub-classes I'm repeating myself, as I just change the constructor to set different initial values to key and dmg, and simply copy and paste the set method. Is there a 'good' way to do this?

    Read the article

< Previous Page | 272 273 274 275 276 277 278 279 280 281 282 283  | Next Page >