Search Results

Search found 8749 results on 350 pages for 'nullable types'.

Page 148/350 | < Previous Page | 144 145 146 147 148 149 150 151 152 153 154 155  | Next Page >

  • Another C datatypes question

    - by b-gen-jack-o-neill
    Hello. Well, I completely get the most basic datatypes of C, like short, int, long, float, to be exact, all numerical types.These types are needed to be known perform right operations with right numbers. For example to use FPU to add two float numbers. So the compiler must know what the type is. But, when it comes to characters I am little bit off. I know that basic C datatype char is there for ASCII characters coding. But what I don´t know is, why you even need another datatype for characters. Why could not you just use 1 byte integer value to store ASCII character. If you call printf, you apecify the datatype in the call, so you could say to printf that the integer represents ASCII character. I dont know how cout resolves datatype, but I guess you could just specify it somehow. Another thing is, when you want to use Unicode, you must use datatype wchar. But, what if I would like to use some another, for example ISO, or Windows coding instead of UTF? Becouse wchar codes characters as UTF-16 or UTF-32 (I read its compiler specific). And, what if I would want to use for example some imaginary new 8 byte text coding? What datatype should I use for it? I am actually pretty confused of this, becouse I always expected that if I want to use UTF-32 instead of ASCII, I just tell compiler "get UTF-32 value of the character I typed and save it into 4 char field." I thought that text coding is to be dealt with by the end, print function for example. That I just need to specify the coding for the compiler to use, since Windows doesent use ASCII in win32 apps, I guess C compiler must convert the char I typed to ASCII from whatever the type is that windows sends to the C editor. And the last thing is, what if I want to use for example 25 Byte integer for some high math operations? C has no specify-yourself datatype. Yes, I know that this would be difficult since all the math operations would need to be changed, becouse CPU can not add 25 Bytes numbers together. But is there a way to do it? Or is there some math library for it? What if I want to compute Pi to 1000000000000000 digits? :) I know my question is pretty long, but I just wanted to explain my thoughts the best I can in English, since its not my native language it is difficult. And I believe there is simple answer to my question(s), something I missed that explains everything. I read lot about text coding, C tutorials, but nothing about his. Thank you for your time.

    Read the article

  • Interface in a dynamic language?

    - by Bryan
    Interface (or an abstract class with all the methods abstract) is a powerful weapon in a static language. It allows different derived types to be used in a uniformed way. However, in a dynamic language, all objects can be used in a uniformed way as long as they define certain methods. Does interface exist in dynamic languages? It seems unnecessary to me.

    Read the article

  • How to avoid overflow in expr. A * B - C * D

    - by Ir0nm
    I need to compute an expression which looks like: A*B - C*D, where their types are: signed long long int A, B, C, D; Each number can be really big (not overflowing its type). While A*B could cause overflow, at same time expression A*B - C*D can be really small. How can I compute it correctly? For example: MAX * MAX - (MAX - 1) * (MAX + 1) == 1, where MAX = LLONG_MAX - n and n - some natural number.

    Read the article

  • Dynamic data-entry value store

    - by simendsjo
    I'm creating a data-entry application where users are allowed to create the entry schema. My first version of this just created a single table per entry schema with each entry spanning a single or multiple columns (for complex types) with the appropriate data type. This allowed for "fast" querying (on small datasets as I didn't index all columns) and simple synchronization where the data-entry was distributed on several databases. I'm not quite happy with this solution though; the only positive thing is the simplicity... I can only store a fixed number of columns. I need to create indexes on all columns. I need to recreate the table on schema changes. Some of my key design criterias are: Very fast querying (Using a simple domain specific query language) Writes doesn't have to be fast Many concurrent users Schemas will change often Schemas might contain many thousand columns The data-entries might be distributed and needs syncronization. Preferable MySQL and SQLite - Databases like DB2 and Oracle is out of the question. Using .Net/Mono I've been thinking of a couple of possible designs, but none of them seems like a good choice. Solution 1: Union like table containing a Type column and one nullable column per type. This avoids joins, but will definitly use a lot of space. Solution 2: Key/value store. All values are stored as string and converted when needed. Also use a lot of space, and of course, I hate having to convert everything to string. Solution 3: Use an xml database or store values as xml. Without any experience I would think this is quite slow (at least for the relational model unless there is some very good xpath support). I also would like to avoid an xml database as other parts of the application fits better as a relational model, and being able to join the data is helpful. I cannot help to think that someone has solved (some of) this already, but I'm unable to find anything. Not quite sure what to search for either... I know market research is doing something like this for their questionnaires, but there are few open source implementations, and the ones I've found doesn't quite fit the bill. PSPP has much of the logic I'm thinking of; primitive column types, many columns, many rows, fast querying and merging. Too bad it doesn't work against a database.. And of course... I don't need 99% of the provided functionality, but a lot of stuff not included. I'm not sure this is the right place to ask such a design related question, but I hope someone here has some tips, know of any existing work, or can point me to a better place to ask such a question. Thanks in advance!

    Read the article

  • Inno Setup install for another user

    - by Steve
    When a user has restricted rights on his/her computer and runs my Inno Setup installer, Windows pop-up an administrator login prompt. The problem is that when the administrator types in his/her username and password and logs-in, Inno Setup thinks that he or she is the logged in user and installs my app for that user instead of the original one. (I'm installing files in the {userappdata} dir) Is there a way to overcome this limitation and install for the original restricted user?

    Read the article

  • Mysql Text Storage?

    - by mii
    I was wondering if you where to have an article or articles with huge amounts of text, what would be better when creating the database structure for the articles text? And why? What will be the advantages or disadvantages if any?. I was thinking of using one of the data types below to hold the articles text for the MySQL database. VARCHAR TEXT MEDIUMTEXT LONGTEXT

    Read the article

  • Is there any reason for an object pool to not be treated as a singleton?

    - by Chris Charabaruk
    I don't necessarily mean implemented using the singleton pattern, but rather, only having and using one instance of a pool. I don't like the idea of having just one pool (or one per pooled type). However, I can't really come up with any concrete situations where there's an advantage to multiple pools for mutable types, at least not any where a single pool can function just as well. What advantages are there to having multiple pools over a singleton pool?

    Read the article

  • C precision of double: compiler dependent?

    - by yCalleecharan
    Hi,on my 32-bit machine (with an Intel T7700 duo core), I have 15 precision digits for both double and long double types for the C language. I compared the parameters LDBL_DIG for long doubles and DBL_DIG for doubles and they are both 15. I got these answers using MVS2008. I was wondering if these results can be compiler dependent or do they just depend on my processor? Thanks a lot...

    Read the article

  • xsd and wsdl incorrect file

    - by Gandalf StormCrow
    How to fix corrupted xsd and wsdl files, is there any IDE which can suggest what is wrong? such as eclipse for java code when pressing CTRL + 1 , or where can I find books tutorials to understand formatting of these file types better? thank you Here is concrete message error I have [ERROR] 'item' is already defined line 223 of file:/C:/project/src/main/resources/schema.xsd [ERROR] (related to above error) the first definition appears here line 22 of file:/C:/project/src/main/resources/schema.xsd

    Read the article

  • In a bidirectional JPA OneToMany/ManyToOne association, what is meant by "the inverse side of the as

    - by Bytecode Ninja
    In these examples on TopLink JPA Annotation Reference: Example 1-59 @OneToMany - Customer Class With Generics @Entity public class Customer implements Serializable { ... @OneToMany(cascade=ALL, mappedBy="customer") public Set<Order> getOrders() { return orders; } ... } Example 1-60 @ManyToOne - Order Class With Generics @Entity public class Order implements Serializable { ... @ManyToOne @JoinColumn(name="CUST_ID", nullable=false) public Customer getCustomer() { return customer; } ... } It seams to me that the Customer entity is the owner of the association. However, in the explanation for the mappedBy attribute in the same document, it is written that: if the relationship is bidirectional, then set the mappedBy element on the inverse (non-owning) side of the association to the name of the field or property that owns the relationship as Example 1-60 shows. However, if I am not wrong, looks like in the example the mappedBy is actually specified on the owning side of the association, rather than the non-owning side. So my question is basically: In a bidirectional (one-to-many/many-to-one) association, which of the entities is the owner? How can we designate the One side as the owner? How can we designate the Many side as the owner? What is meant by "the inverse side of the association"? How can we designate the One side as the inverse? How can we designate the Many side as the inverse? Thanks in advance.

    Read the article

  • Make Visual Studios "Add Service Reference" Feature use an existing Class

    - by gencha
    When I add a service reference to my Visual Studio 2010 C# project, a new class for one of the types defined in the WSDL will be generated. A de-facto equivalent definition of that type already exists in our solution in a different assembly. When adding the SoapTypeAttribute to the existing class and replacing the references to the generated class in the generated code, everything runs perfectly and as expected. How would I tell Visual Studio to use the existing class in the generated code?

    Read the article

  • dual map structure implementation?

    - by Danra
    Hey, I'm looking for a standard dual-map structure - is there one implemented in std/boost/another standard C++ library? When I say "dual-map" I mean a map which can be indexed efficiently both by the key and the "value" (it actually has two key types instead of one key type and one value type). for example: dualmap<int,string> m; m[1] = "foo"; m["bar"] = 2 int a = m["bar"]; // a = 2 Thanks, Dan

    Read the article

  • Do you gain any operations when you constrain a generic type using where T : struct?

    - by Fiona Holder
    This may be a bit of an abstract question, so apologies in advance. I am looking into generics in .NET, and was wondering about the where T : struct constraint. I understand that this allows you to restrict the type used to be a value type. My question is, without any type constraint, you can do a limited number of operations on T. Do you gain the ability to use any additional operations when you specify where T : struct, or is the only value in restricting the types you can pass in?

    Read the article

  • Where can one find free software icons / images?

    - by mmattax
    This may not be directly related to programming, but I always find it hard to get quality icons that can be used for software. I currently have the need for some type of "green checkmark image", and I always seem to be looking for print, save, delete types of icons... Anybody have good resources? Note: I rather not be stealing someone's intellectual property.

    Read the article

  • Rating mechanisms

    - by Jasie
    Is there any place that showcases a bunch of different types of rating systems (like using multiple sliders, star ratings, up/down votes)? I'm trying to get ideas for a better rating system than just up/down (more criteria). (I'm not interested in the backend, but the human/computer interaction part of it).

    Read the article

  • How to implement an interface member that returns void in F#

    - by Drew Noakes
    Imagine the following interface in C#: interface IFoo { void Bar(); } How can I implement this in F#? All the examples I've found during 30 minutes of searching online show only examples that have return types which I suppose is more common in a functional style, but something I can't avoid in this instance. Here's what I have so far: type Bar() = interface IFoo with member this.Bar = void Fails with FS0010: Unexpected keyword 'void' in expression.

    Read the article

  • Can't start rails server after 3.0.1 upgrade

    - by Alberto
    Followed instructions on Railscast but can't get server to start. It states the following error: $ rails s script/rails:6:in `require': no such file to load -- rails/commands (LoadError)` from script/rails:6:in `<main>' Saw the answer on this related question but my Gemfile has no reference to any rails 2.x version and in the "bundle install" results i get this in the results: "Using rails (3.0.1)" EDIT: (adding Gemfile.lock details) GEM remote: http://rubygems.org/ specs: abstract (1.0.0) actionmailer (3.0.1) actionpack (= 3.0.1) mail (~> 2.2.5) actionpack (3.0.1) activemodel (= 3.0.1) activesupport (= 3.0.1) builder (~> 2.1.2) erubis (~> 2.6.6) i18n (~> 0.4.1) rack (~> 1.2.1) rack-mount (~> 0.6.12) rack-test (~> 0.5.4) tzinfo (~> 0.3.23) activemodel (3.0.1) activesupport (= 3.0.1) builder (~> 2.1.2) i18n (~> 0.4.1) activerecord (3.0.1) activemodel (= 3.0.1) activesupport (= 3.0.1) arel (~> 1.0.0) tzinfo (~> 0.3.23) activeresource (3.0.1) activemodel (= 3.0.1) activesupport (= 3.0.1) activesupport (3.0.1) arel (1.0.1) activesupport (~> 3.0.0) builder (2.1.2) calendar_date_select (1.16.1) erubis (2.6.6) abstract (>= 1.0.0) googlecharts (1.6.0) i18n (0.4.2) mail (2.2.9) activesupport (>= 2.3.6) i18n (~> 0.4.1) mime-types (~> 1.16) treetop (~> 1.4.8) mechanize (1.0.0) nokogiri (>= 1.2.1) mime-types (1.16) nokogiri (1.4.3.1) pg (0.9.0) polyglot (0.3.1) rack (1.2.1) rack-mount (0.6.13) rack (>= 1.0.0) rack-test (0.5.6) rack (>= 1.0) rails (3.0.1) actionmailer (= 3.0.1) actionpack (= 3.0.1) activerecord (= 3.0.1) activeresource (= 3.0.1) activesupport (= 3.0.1) bundler (~> 1.0.0) railties (= 3.0.1) railties (3.0.1) actionpack (= 3.0.1) activesupport (= 3.0.1) rake (>= 0.8.4) thor (~> 0.14.0) rake (0.8.7) sparklines (0.5.2) thor (0.14.4) treetop (1.4.8) polyglot (>= 0.3.1) tzinfo (0.3.23) PLATFORMS ruby DEPENDENCIES calendar_date_select googlecharts mechanize pg rails (= 3.0.1) sparklines EDIT: (adding Boot.rb details) require 'rubygems' # Set up gems listed in the Gemfile. gemfile = File.expand_path('../../Gemfile', __FILE__) begin ENV['BUNDLE_GEMFILE'] = gemfile require 'bundler' Bundler.setup rescue Bundler::GemNotFound => e STDERR.puts e.message STDERR.puts "Try running `bundle install`." exit! end if File.exist?(gemfile)

    Read the article

  • Const unsigned char* to char8

    - by BSchlinker
    So, I have two types at the moment: const unsigned char* unencrypted_data_char; string unencrypted_data; I'm attempting to perform a simple conversion of data from one to the other (string - const unsigned char*) As a result, I have the following: strcpy((unencrypted_data_char),(unencrypted_data.c_str())); However, I'm receiving the error: error C2664: 'strcpy' : cannot convert parameter 1 from 'const unsigned char *' to 'char *' Any advise? I thought using reinterpret_cast would help, but it doesn't seem to make a difference.

    Read the article

  • What is the minimum interface that has the Count property in .Net

    - by SoMoS
    Hello, I need to change a method that has one parameter that takes a serie of objects. I need to find the lowest Interface (in inheritance tree) that has the Count property. Until now I was using the IEnumerable but as this has not Count I need to change it to the wider interface possible so the method can work with the biggest number of types of series (collections, lists, arrays, etc). Thanks in advance.

    Read the article

  • Avoiding secondary selects or joins with Hibernate Criteria or HQL query

    - by Ben Benson
    I am having trouble optimizing Hibernate queries to avoid performing joins or secondary selects. When a Hibernate query is performed (criteria or hql), such as the following: return getSession().createQuery(("from GiftCard as card where card.recipientNotificationRequested=1").list(); ... and the where clause examines properties that do not require any joins with other tables... but Hibernate still performs a full join with other tables (or secondary selects depending on how I set the fetchMode). The object in question (GiftCard) has a couple ManyToOne associations that I would prefer to be lazily loaded in this case (but not necessarily all cases). I want a solution that I can control what is lazily loaded when I perform the query. Here's what the GiftCard Entity looks like: @Entity @Table(name = "giftCards") public class GiftCard implements Serializable { private static final long serialVersionUID = 1L; private String id_; private User buyer_; private boolean isRecipientNotificationRequested_; @Id public String getId() { return this.id_; } public void setId(String id) { this.id_ = id; } @ManyToOne @JoinColumn(name = "buyerUserId") @NotFound(action = NotFoundAction.IGNORE) public User getBuyer() { return this.buyer_; } public void setBuyer(User buyer) { this.buyer_ = buyer; } @Column(name="isRecipientNotificationRequested", nullable=false, columnDefinition="tinyint") public boolean isRecipientNotificationRequested() { return this.isRecipientNotificationRequested_; } public void setRecipientNotificationRequested(boolean isRecipientNotificationRequested) { this.isRecipientNotificationRequested_ = isRecipientNotificationRequested; } }

    Read the article

< Previous Page | 144 145 146 147 148 149 150 151 152 153 154 155  | Next Page >