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  • division problems

    - by David
    This line of code: System.out.println ("aray[j], "+aray[j]+", divided by sum, "+sum+", equals: aray[j]/sum: "+ aray[j]/sum) ; is yeilding this line of text: aray[j], 21, divided by sum, 100, equals: aray[j]/sum: 0 why is it doing this? (everything is right eccept that the answer should be .21)

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  • Lifting a math symbol in LaTeX

    - by Chris Conway
    I'm using the symbol \otimes as a unary operator and it's vertical alignment doesn't seem right to me. It wants to sit a bit below the baseline: and I tried using \raisebox to fix this, e.g., \raisebox{1pt}{$\otimes$}: But \raisebox doesn't seem to be sensitive to subscripts. The operator stays the same size while everything around it shrinks: The problem, I think, is that \raisebox creates its own LR box, which doesn't inherit the settings in the surrounding math environment. Is there a version of \raisebox that "respects math"?

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  • by reference in C++

    - by lego69
    I have this snippet of the code Stack& Stack:: operator=(const Stack& stack){ if(this == &stack){ return *this } } here I define operator = but I can't understand, if I receive by reference stack why it should be & in this == &stack and not this == stack and why we return * in return *this and not this thanks in advance for any help

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  • How to return the number of a month in C# function

    - by john
    I want to return the number of a month and i made a function but it always returns 0 this is my code: public int getNrMonth(String s) { int nr=0; if (s.Equals("January")) nr = 1 if (s.Equals("February")) nr = 2; return nr; } Could someone tell me wath is wrong please? I'm beginner!

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  • object reference set in java

    - by landon9720
    I need to create a Set of objects. The concern is I do not want to base the hashing or the equality on the objects' hashCode and equals implementation. Instead, I want the hash code and equality to be based only on each object's reference identity (i.e.: the value of the reference pointer). I'm not sure how to do this in Java. The reasoning behind this is my objects do not reliably implement equals or hashCode, and in this case reference identity is good enough.

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  • What am I calling?

    - by Knowing me knowing you
    Is there a way to check inside a fnc what is this fnc name? I'm working currently on LargeInt class and I've realized that code for oparator and operator< is almost identical so I would like to know what operator is calling me and react accordingly. Thank you.

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  • safe dereferencing and deletion

    - by serejko
    Hi, I'm relatively new to C++ and OOP in general and currently trying to make such a class that allows to dereference and delete a dead or invalid pointer without any care of having undefined behavior or program fault in result, and I want to ask you is it a good idea and is there something similar which is already implemented by someone else? or maybe I'm doing something completely wrong? I've just started making it and here is the code I currently have: template<class T> class SafeDeref { public: T& operator *() { hash_set<T*>::iterator it = theStore.find(reinterpret_cast<T*>(ptr)); if (it != theStore.end()) return *this; return theDefaultObject; } T* operator ->() { hash_set<T*>::iterator it = theStore.find(reinterpret_cast<T*>(ptr)); if (it != theStore.end()) return this; return &theDefaultObject; } void* operator new(size_t size) { void* ptr = malloc(size * sizeof(T)); if (ptr != 0) theStore.insert(reinterpret_cast<T*>(ptr)); return ptr; } void operator delete(void* ptr) { hash_set<T*>::iterator it = theStore.find(reinterpret_cast<T*>(ptr)); if (it != theStore.end()) { theStore.erase(it); free(ptr); } } protected: static bool isInStore(T* ptr) { return theStore.find(ptr) != theStore.end(); } private: static T theDefaultObject; static hash_set<T*> theStore; }; The idea is that each class with the safe dereference should be inherited from it like this: class Foo : public SafeDeref<Foo> { void doSomething(); }; So... Any advices? Thanks in advance. P.S. If you're wondering why I need this... well, I'm creating a set of native functions for some scripting environment, and all of them use pointers to internally allocated objects as handles to them and they're able to delete them as well (input data can be wrong), so this is kinda protection from damaging host application's memory And I really sorry for my bad English

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  • C++ require that one template type is derived from the other

    - by Will
    In a comparison operator: template<class R1, class R2> bool operator==(Manager<R1> m1, Manager<R2> m2) { return p1.internal_field == p2.internal_field; } Is there any way I could enforce that R1 and R2 must have a supertype or subtype relation? That is, I'd like to allow either R1 to be derived from R2, or R2 to be derived from R1, but disallow the comparison if R1 and R2 are unrelated types.

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  • Change query to use a LEFT join

    - by Craig
    I have a query which is failing, as it needs to be using LEFT JOIN, as opposed to the default INNER JOIN used by the 'join' syntax: var users = (from u in this._context.Users join p in this._context.Profiles on u.ProfileID equals p.ID join vw in this._context.vw_Contacts on u.ContactID equals vw.ID orderby u.Code select new { ID = u.ID, profileId = p.ID, u.ContactID, u.Code, u.UserName, vw.FileAs, p.Name, u.LastLogout, u.Inactive, u.Disabled }).ToList(); How would i re-write this so that is utilises a LEFT join?

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  • A first look at ConfORM - Part 1

    - by thangchung
    All source codes for this post can be found at here.Have you ever heard of ConfORM is not? I have read it three months ago when I wrote an post about NHibernate and Autofac. At that time, this project really has just started and still in beta version, so I still do not really care much. But recently when reading a book by Jason Dentler NHibernate 3.0 Cookbook, I started to pay attention to it. Author have mentioned quite a lot of OSS in his book. And now again I have reviewed ConfORM once again. I have been involved in ConfORM development group on google and read some articles about it. Fabio Maulo spent a lot of work for the OSS, and I hope it will adapt a great way for NHibernate (because he contributed to NHibernate that). So what is ConfORM? It is stand for Configuration ORM, and it was trying to use a lot of heuristic model for identifying entities from C# code. Today, it's mostly Model First Driven development, so the first thing is to build the entity model. This is really important and we can see it is the heart of business software. Then we have to tell DB about the entity of this model. We often will use Inversion Engineering here, Database Schema is will create based on recently Entity Model. From now we will absolutely not interested in the DB again, only focus on the Entity Model.Fluent NHibenate really good, I liked this OSS. Sharp Architecture and has done so well in Fluent NHibernate integration with applications. A Multiple Database technical in Sharp Architecture is truly awesome. It can receive configuration, a connection string and a dll containing entity model, which would then create a SessionFactory, finally caching inside the computer memory. As the number of SessionFactory can be very large and will full of the memory, it has also devised a way of caching SessionFactory in the file. This post I hope this will not completely explain about and building a model of multiple databases. I just tried to mount a number of posts from the community and apply some of my knowledge to build a management model Session for ConfORM.As well as Fluent NHibernate, ConfORM also supported on the interface mapping, see this to understand it. So the first thing we will build the Entity Model for it, and here is what I will use the model for this article. A simple model for managing news and polls, it will be too easy for a number of people, but I hope not to bring complexity to this post.I will then have some code to build super type for the Entity Model. public interface IEntity<TId>    {        TId Id { get; set; }    } public abstract class EntityBase<TId> : IEntity<TId>    {        public virtual TId Id { get; set; }         public override bool Equals(object obj)        {            return Equals(obj as EntityBase<TId>);        }         private static bool IsTransient(EntityBase<TId> obj)        {            return obj != null &&            Equals(obj.Id, default(TId));        }         private Type GetUnproxiedType()        {            return GetType();        }         public virtual bool Equals(EntityBase<TId> other)        {            if (other == null)                return false;            if (ReferenceEquals(this, other))                return true;            if (!IsTransient(this) &&            !IsTransient(other) &&            Equals(Id, other.Id))            {                var otherType = other.GetUnproxiedType();                var thisType = GetUnproxiedType();                return thisType.IsAssignableFrom(otherType) ||                otherType.IsAssignableFrom(thisType);            }            return false;        }         public override int GetHashCode()        {            if (Equals(Id, default(TId)))                return base.GetHashCode();            return Id.GetHashCode();        }    } Database schema will be created as:The next step is to build the ConORM builder to create a NHibernate Configuration. Patrick have a excellent article about it at here. Contract of it below: public interface IConfigBuilder    {        Configuration BuildConfiguration(string connectionString, string sessionFactoryName);    } The idea here is that I will pass in a connection string and a set of the DLL containing the Entity Model and it makes me a NHibernate Configuration (shame that I stole this ideas of Sharp Architecture). And here is its code: public abstract class ConfORMConfigBuilder : RootObject, IConfigBuilder    {        private static IConfigurator _configurator;         protected IEnumerable<Type> DomainTypes;         private readonly IEnumerable<string> _assemblies;         protected ConfORMConfigBuilder(IEnumerable<string> assemblies)            : this(new Configurator(), assemblies)        {            _assemblies = assemblies;        }         protected ConfORMConfigBuilder(IConfigurator configurator, IEnumerable<string> assemblies)        {            _configurator = configurator;            _assemblies = assemblies;        }         public abstract void GetDatabaseIntegration(IDbIntegrationConfigurationProperties dBIntegration, string connectionString);         protected abstract HbmMapping GetMapping();         public Configuration BuildConfiguration(string connectionString, string sessionFactoryName)        {            Contract.Requires(!string.IsNullOrEmpty(connectionString), "ConnectionString is null or empty");            Contract.Requires(!string.IsNullOrEmpty(sessionFactoryName), "SessionFactory name is null or empty");            Contract.Requires(_configurator != null, "Configurator is null");             return CatchExceptionHelper.TryCatchFunction(                () =>                {                    DomainTypes = GetTypeOfEntities(_assemblies);                     if (DomainTypes == null)                        throw new Exception("Type of domains is null");                     var configure = new Configuration();                    configure.SessionFactoryName(sessionFactoryName);                     configure.Proxy(p => p.ProxyFactoryFactory<ProxyFactoryFactory>());                    configure.DataBaseIntegration(db => GetDatabaseIntegration(db, connectionString));                     if (_configurator.GetAppSettingString("IsCreateNewDatabase").ConvertToBoolean())                    {                        configure.SetProperty("hbm2ddl.auto", "create-drop");                    }                     configure.Properties.Add("default_schema", _configurator.GetAppSettingString("DefaultSchema"));                    configure.AddDeserializedMapping(GetMapping(),                                                     _configurator.GetAppSettingString("DocumentFileName"));                     SchemaMetadataUpdater.QuoteTableAndColumns(configure);                     return configure;                }, Logger);        }         protected IEnumerable<Type> GetTypeOfEntities(IEnumerable<string> assemblies)        {            var type = typeof(EntityBase<Guid>);            var domainTypes = new List<Type>();             foreach (var assembly in assemblies)            {                var realAssembly = Assembly.LoadFrom(assembly);                 if (realAssembly == null)                    throw new NullReferenceException();                 domainTypes.AddRange(realAssembly.GetTypes().Where(                    t =>                    {                        if (t.BaseType != null)                            return string.Compare(t.BaseType.FullName,                                          type.FullName) == 0;                        return false;                    }));            }             return domainTypes;        }    } I do not want to dependency on any RDBMS, so I made a builder as an abstract class, and so I will create a concrete instance for SQL Server 2008 as follows: public class SqlServerConfORMConfigBuilder : ConfORMConfigBuilder    {        public SqlServerConfORMConfigBuilder(IEnumerable<string> assemblies)            : base(assemblies)        {        }         public override void GetDatabaseIntegration(IDbIntegrationConfigurationProperties dBIntegration, string connectionString)        {            dBIntegration.Dialect<MsSql2008Dialect>();            dBIntegration.Driver<SqlClientDriver>();            dBIntegration.KeywordsAutoImport = Hbm2DDLKeyWords.AutoQuote;            dBIntegration.IsolationLevel = IsolationLevel.ReadCommitted;            dBIntegration.ConnectionString = connectionString;            dBIntegration.LogSqlInConsole = true;            dBIntegration.Timeout = 10;            dBIntegration.LogFormatedSql = true;            dBIntegration.HqlToSqlSubstitutions = "true 1, false 0, yes 'Y', no 'N'";        }         protected override HbmMapping GetMapping()        {            var orm = new ObjectRelationalMapper();             orm.Patterns.PoidStrategies.Add(new GuidPoidPattern());             var patternsAppliers = new CoolPatternsAppliersHolder(orm);            //patternsAppliers.Merge(new DatePropertyByNameApplier()).Merge(new MsSQL2008DateTimeApplier());            patternsAppliers.Merge(new ManyToOneColumnNamingApplier());            patternsAppliers.Merge(new OneToManyKeyColumnNamingApplier(orm));             var mapper = new Mapper(orm, patternsAppliers);             var entities = new List<Type>();             DomainDefinition(orm);            Customize(mapper);             entities.AddRange(DomainTypes);             return mapper.CompileMappingFor(entities);        }         private void DomainDefinition(IObjectRelationalMapper orm)        {            orm.TablePerClassHierarchy(new[] { typeof(EntityBase<Guid>) });            orm.TablePerClass(DomainTypes);             orm.OneToOne<News, Poll>();            orm.ManyToOne<Category, News>();             orm.Cascade<Category, News>(Cascade.All);            orm.Cascade<News, Poll>(Cascade.All);            orm.Cascade<User, Poll>(Cascade.All);        }         private static void Customize(Mapper mapper)        {            CustomizeRelations(mapper);            CustomizeTables(mapper);            CustomizeColumns(mapper);        }         private static void CustomizeRelations(Mapper mapper)        {        }         private static void CustomizeTables(Mapper mapper)        {        }         private static void CustomizeColumns(Mapper mapper)        {            mapper.Class<Category>(                cm =>                {                    cm.Property(x => x.Name, m => m.NotNullable(true));                    cm.Property(x => x.CreatedDate, m => m.NotNullable(true));                });             mapper.Class<News>(                cm =>                {                    cm.Property(x => x.Title, m => m.NotNullable(true));                    cm.Property(x => x.ShortDescription, m => m.NotNullable(true));                    cm.Property(x => x.Content, m => m.NotNullable(true));                });             mapper.Class<Poll>(                cm =>                {                    cm.Property(x => x.Value, m => m.NotNullable(true));                    cm.Property(x => x.VoteDate, m => m.NotNullable(true));                    cm.Property(x => x.WhoVote, m => m.NotNullable(true));                });             mapper.Class<User>(                cm =>                {                    cm.Property(x => x.UserName, m => m.NotNullable(true));                    cm.Property(x => x.Password, m => m.NotNullable(true));                });        }    } As you can see that we can do so many things in this class, such as custom entity relationships, custom binding on the columns, custom table name, ... Here I only made two so-Appliers for OneToMany and ManyToOne relationships, you can refer to it here public class ManyToOneColumnNamingApplier : IPatternApplier<PropertyPath, IManyToOneMapper>    {        #region IPatternApplier<PropertyPath,IManyToOneMapper> Members         public void Apply(PropertyPath subject, IManyToOneMapper applyTo)        {            applyTo.Column(subject.ToColumnName() + "Id");        }         #endregion         #region IPattern<PropertyPath> Members         public bool Match(PropertyPath subject)        {            return subject != null;        }         #endregion    } public class OneToManyKeyColumnNamingApplier : OneToManyPattern, IPatternApplier<PropertyPath, ICollectionPropertiesMapper>    {        public OneToManyKeyColumnNamingApplier(IDomainInspector domainInspector) : base(domainInspector) { }         #region Implementation of IPattern<PropertyPath>         public bool Match(PropertyPath subject)        {            return Match(subject.LocalMember);        }         #endregion Implementation of IPattern<PropertyPath>         #region Implementation of IPatternApplier<PropertyPath,ICollectionPropertiesMapper>         public void Apply(PropertyPath subject, ICollectionPropertiesMapper applyTo)        {            applyTo.Key(km => km.Column(GetKeyColumnName(subject)));        }         #endregion Implementation of IPatternApplier<PropertyPath,ICollectionPropertiesMapper>         protected virtual string GetKeyColumnName(PropertyPath subject)        {            Type propertyType = subject.LocalMember.GetPropertyOrFieldType();            Type childType = propertyType.DetermineCollectionElementType();            var entity = subject.GetContainerEntity(DomainInspector);            var parentPropertyInChild = childType.GetFirstPropertyOfType(entity);            var baseName = parentPropertyInChild == null ? subject.PreviousPath == null ? entity.Name : entity.Name + subject.PreviousPath : parentPropertyInChild.Name;            return GetKeyColumnName(baseName);        }         protected virtual string GetKeyColumnName(string baseName)        {            return string.Format("{0}Id", baseName);        }    } Everyone also can download the ConfORM source at google code and see example inside it. Next part I will write about multiple database factory. Hope you enjoy about it. happy coding and see you next part.

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  • Should this immutable struct be a mutable class?

    - by ChaosPandion
    I showed this struct to a fellow programmer and they felt that it should be a mutable class. They felt it is inconvenient not to have null references and the ability to alter the object as required. I would really like to know if there are any other reasons to make this a mutable class. [Serializable] public struct PhoneNumber : ICloneable, IEquatable<PhoneNumber> { private const int AreaCodeShift = 54; private const int CentralOfficeCodeShift = 44; private const int SubscriberNumberShift = 30; private const int CentralOfficeCodeMask = 0x000003FF; private const int SubscriberNumberMask = 0x00003FFF; private const int ExtensionMask = 0x3FFFFFFF; private readonly ulong value; public int AreaCode { get { return UnmaskAreaCode(value); } } public int CentralOfficeCode { get { return UnmaskCentralOfficeCode(value); } } public int SubscriberNumber { get { return UnmaskSubscriberNumber(value); } } public int Extension { get { return UnmaskExtension(value); } } public PhoneNumber(ulong value) : this(UnmaskAreaCode(value), UnmaskCentralOfficeCode(value), UnmaskSubscriberNumber(value), UnmaskExtension(value), true) { } public PhoneNumber(int areaCode, int centralOfficeCode, int subscriberNumber) : this(areaCode, centralOfficeCode, subscriberNumber, 0, true) { } public PhoneNumber(int areaCode, int centralOfficeCode, int subscriberNumber, int extension) : this(areaCode, centralOfficeCode, subscriberNumber, extension, true) { } private PhoneNumber(int areaCode, int centralOfficeCode, int subscriberNumber, int extension, bool throwException) { value = 0; if (areaCode < 200 || areaCode > 989) { if (!throwException) return; throw new ArgumentOutOfRangeException("areaCode", areaCode, @"The area code portion must fall between 200 and 989."); } else if (centralOfficeCode < 200 || centralOfficeCode > 999) { if (!throwException) return; throw new ArgumentOutOfRangeException("centralOfficeCode", centralOfficeCode, @"The central office code portion must fall between 200 and 999."); } else if (subscriberNumber < 0 || subscriberNumber > 9999) { if (!throwException) return; throw new ArgumentOutOfRangeException("subscriberNumber", subscriberNumber, @"The subscriber number portion must fall between 0 and 9999."); } else if (extension < 0 || extension > 1073741824) { if (!throwException) return; throw new ArgumentOutOfRangeException("extension", extension, @"The extension portion must fall between 0 and 1073741824."); } else if (areaCode.ToString()[1] - 48 > 8) { if (!throwException) return; throw new ArgumentOutOfRangeException("areaCode", areaCode, @"The second digit of the area code cannot be greater than 8."); } else { value |= ((ulong)(uint)areaCode << AreaCodeShift); value |= ((ulong)(uint)centralOfficeCode << CentralOfficeCodeShift); value |= ((ulong)(uint)subscriberNumber << SubscriberNumberShift); value |= ((ulong)(uint)extension); } } public object Clone() { return this; } public override bool Equals(object obj) { return obj != null && obj.GetType() == typeof(PhoneNumber) && Equals((PhoneNumber)obj); } public bool Equals(PhoneNumber other) { return this.value == other.value; } public override int GetHashCode() { return value.GetHashCode(); } public override string ToString() { return ToString(PhoneNumberFormat.Separated); } public string ToString(PhoneNumberFormat format) { switch (format) { case PhoneNumberFormat.Plain: return string.Format(@"{0:D3}{1:D3}{2:D4} {3:#}", AreaCode, CentralOfficeCode, SubscriberNumber, Extension).Trim(); case PhoneNumberFormat.Separated: return string.Format(@"{0:D3}-{1:D3}-{2:D4} {3:#}", AreaCode, CentralOfficeCode, SubscriberNumber, Extension).Trim(); default: throw new ArgumentOutOfRangeException("format"); } } public ulong ToUInt64() { return value; } public static PhoneNumber Parse(string value) { var result = default(PhoneNumber); if (!TryParse(value, out result)) { throw new FormatException(string.Format(@"The string ""{0}"" could not be parsed as a phone number.", value)); } return result; } public static bool TryParse(string value, out PhoneNumber result) { result = default(PhoneNumber); if (string.IsNullOrEmpty(value)) { return false; } var index = 0; var numericPieces = new char[value.Length]; foreach (var c in value) { if (char.IsNumber(c)) { numericPieces[index++] = c; } } if (index < 9) { return false; } var numericString = new string(numericPieces); var areaCode = int.Parse(numericString.Substring(0, 3)); var centralOfficeCode = int.Parse(numericString.Substring(3, 3)); var subscriberNumber = int.Parse(numericString.Substring(6, 4)); var extension = 0; if (numericString.Length > 10) { extension = int.Parse(numericString.Substring(10)); } result = new PhoneNumber( areaCode, centralOfficeCode, subscriberNumber, extension, false ); return result.value == 0; } public static bool operator ==(PhoneNumber left, PhoneNumber right) { return left.Equals(right); } public static bool operator !=(PhoneNumber left, PhoneNumber right) { return !left.Equals(right); } private static int UnmaskAreaCode(ulong value) { return (int)(value >> AreaCodeShift); } private static int UnmaskCentralOfficeCode(ulong value) { return (int)((value >> CentralOfficeCodeShift) & CentralOfficeCodeMask); } private static int UnmaskSubscriberNumber(ulong value) { return (int)((value >> SubscriberNumberShift) & SubscriberNumberMask); } private static int UnmaskExtension(ulong value) { return (int)(value & ExtensionMask); } } public enum PhoneNumberFormat { Plain, Separated }

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  • Convert C++Builder AnsiString to std::string via boost::lexical_cast

    - by David Klein
    For a school assignment I have to implement a project in C++ using Borland C++ Builder. As the VCL uses AnsiString for all GUI Components I have to convert all of my std::strings to AnsiString for the sake of displaying. std::string inp = "Hello world!"; AnsiString outp(inp.c_str()); works of course but is a bit tedious to write and code duplication I want to avoid. As we use Boost in other contexts I decided to provide some helper functions go get boost::lexical_cast to work with AnsiString. Here is my implementation so far: std::istream& operator>>(std::istream& istr, AnsiString& str) { istr.exceptions(std::ios::badbit | std::ios::failbit | std::ios::eofbit); std::string s; std::getline(istr,s); str = AnsiString(s.c_str()); return istr; } In the beginning I got Access Violation after Access Violation but since I added the .exceptions() stuff the picture gets clearer. When the conversion is performed I get the following Exception: ios_base::eofbit set [Runtime Error/std::ios_base::failure] Does anyone have an idea how to fix it and can explain why the error occurs? My C++ experience is very limited. The conversion routine the other way round would be: std::ostream& operator<<(std::ostream& ostr,const AnsiString& str) { ostr << (str.c_str()); return ostr; } Maybe someone will spot an error here too :) With best regards! Edit: At the moment I'm using the edited version of Jem, it works in the beginning. After a while of using the programm the Borland Codeguard mentions some pointer arithmetic in already freed regions. Any ideas how this could be related? The Codeguard log (I'm using the german version, translations marked with stars): ------------------------------------------ Fehler 00080. 0x104230 (r) (Thread 0x07A4): Zeigerarithmetik in freigegebenem Speicher: 0x0241A238-0x0241A258. **(pointer arithmetic in freed region)** | d:\program files\borland\bds\4.0\include\dinkumware\sstream Zeile 126: | { // not first growth, adjust pointers | _Seekhigh = _Seekhigh - _Mysb::eback() + _Ptr; |> _Mysb::setp(_Mysb::pbase() - _Mysb::eback() + _Ptr, | _Mysb::pptr() - _Mysb::eback() + _Ptr, _Ptr + _Newsize); | if (_Mystate & _Noread) Aufrufhierarchie: **(stack-trace)** 0x00411731(=FOSChampion.exe:0x01:010731) d:\program files\borland\bds\4.0\include\dinkumware\sstream#126 0x00411183(=FOSChampion.exe:0x01:010183) d:\program files\borland\bds\4.0\include\dinkumware\streambuf#465 0x0040933D(=FOSChampion.exe:0x01:00833D) d:\program files\borland\bds\4.0\include\dinkumware\streambuf#151 0x00405988(=FOSChampion.exe:0x01:004988) d:\program files\borland\bds\4.0\include\dinkumware\ostream#679 0x00405759(=FOSChampion.exe:0x01:004759) D:\Projekte\Schule\foschamp\src\Server\Ansistringkonverter.h#31 0x004080C9(=FOSChampion.exe:0x01:0070C9) D:\Projekte\Schule\foschamp\lib\boost_1_34_1\boost/lexical_cast.hpp#151 Objekt (0x0241A238) [Größe: 32 Byte] war erstellt mit new **(Object was created with new)** | d:\program files\borland\bds\4.0\include\dinkumware\xmemory Zeile 28: | _Ty _FARQ *_Allocate(_SIZT _Count, _Ty _FARQ *) | { // allocate storage for _Count elements of type _Ty |> return ((_Ty _FARQ *)::operator new(_Count * sizeof (_Ty))); | } | Aufrufhierarchie: **(stack-trace)** 0x0040ED90(=FOSChampion.exe:0x01:00DD90) d:\program files\borland\bds\4.0\include\dinkumware\xmemory#28 0x0040E194(=FOSChampion.exe:0x01:00D194) d:\program files\borland\bds\4.0\include\dinkumware\xmemory#143 0x004115CF(=FOSChampion.exe:0x01:0105CF) d:\program files\borland\bds\4.0\include\dinkumware\sstream#105 0x00411183(=FOSChampion.exe:0x01:010183) d:\program files\borland\bds\4.0\include\dinkumware\streambuf#465 0x0040933D(=FOSChampion.exe:0x01:00833D) d:\program files\borland\bds\4.0\include\dinkumware\streambuf#151 0x00405988(=FOSChampion.exe:0x01:004988) d:\program files\borland\bds\4.0\include\dinkumware\ostream#679 Objekt (0x0241A238) war Gelöscht mit delete **(Object was deleted with delete)** | d:\program files\borland\bds\4.0\include\dinkumware\xmemory Zeile 138: | void deallocate(pointer _Ptr, size_type) | { // deallocate object at _Ptr, ignore size |> ::operator delete(_Ptr); | } | Aufrufhierarchie: **(stack-trace)** 0x004044C6(=FOSChampion.exe:0x01:0034C6) d:\program files\borland\bds\4.0\include\dinkumware\xmemory#138 0x00411628(=FOSChampion.exe:0x01:010628) d:\program files\borland\bds\4.0\include\dinkumware\sstream#111 0x00411183(=FOSChampion.exe:0x01:010183) d:\program files\borland\bds\4.0\include\dinkumware\streambuf#465 0x0040933D(=FOSChampion.exe:0x01:00833D) d:\program files\borland\bds\4.0\include\dinkumware\streambuf#151 0x00405988(=FOSChampion.exe:0x01:004988) d:\program files\borland\bds\4.0\include\dinkumware\ostream#679 0x00405759(=FOSChampion.exe:0x01:004759) D:\Projekte\Schule\foschamp\src\Server\Ansistringkonverter.h#31 ------------------------------------------ Ansistringkonverter.h is the file with the posted operators and line 31 is: std::ostream& operator<<(std::ostream& ostr,const AnsiString& str) { ostr << (str.c_str()); **(31)** return ostr; } Thanks for your help :)

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  • C#/.NET Little Wonders: Comparer&lt;T&gt;.Default

    - by James Michael Hare
    I’ve been working with a wonderful team on a major release where I work, which has had the side-effect of occupying most of my spare time preparing, testing, and monitoring.  However, I do have this Little Wonder tidbit to offer today. Introduction The IComparable<T> interface is great for implementing a natural order for a data type.  It’s a very simple interface with a single method: 1: public interface IComparer<in T> 2: { 3: // Compare two instances of same type. 4: int Compare(T x, T y); 5: }  So what do we expect for the integer return value?  It’s a pseudo-relative measure of the ordering of x and y, which returns an integer value in much the same way C++ returns an integer result from the strcmp() c-style string comparison function: If x == y, returns 0. If x > y, returns > 0 (often +1, but not guaranteed) If x < y, returns < 0 (often –1, but not guaranteed) Notice that the comparison operator used to evaluate against zero should be the same comparison operator you’d use as the comparison operator between x and y.  That is, if you want to see if x > y you’d see if the result > 0. The Problem: Comparing With null Can Be Messy This gets tricky though when you have null arguments.  According to the MSDN, a null value should be considered equal to a null value, and a null value should be less than a non-null value.  So taking this into account we’d expect this instead: If x == y (or both null), return 0. If x > y (or y only is null), return > 0. If x < y (or x only is null), return < 0. But here’s the problem – if x is null, what happens when we attempt to call CompareTo() off of x? 1: // what happens if x is null? 2: x.CompareTo(y); It’s pretty obvious we’ll get a NullReferenceException here.  Now, we could guard against this before calling CompareTo(): 1: int result; 2:  3: // first check to see if lhs is null. 4: if (x == null) 5: { 6: // if lhs null, check rhs to decide on return value. 7: if (y == null) 8: { 9: result = 0; 10: } 11: else 12: { 13: result = -1; 14: } 15: } 16: else 17: { 18: // CompareTo() should handle a null y correctly and return > 0 if so. 19: result = x.CompareTo(y); 20: } Of course, we could shorten this with the ternary operator (?:), but even then it’s ugly repetitive code: 1: int result = (x == null) 2: ? ((y == null) ? 0 : -1) 3: : x.CompareTo(y); Fortunately, the null issues can be cleaned up by drafting in an external Comparer.  The Soltuion: Comparer<T>.Default You can always develop your own instance of IComparer<T> for the job of comparing two items of the same type.  The nice thing about a IComparer is its is independent of the things you are comparing, so this makes it great for comparing in an alternative order to the natural order of items, or when one or both of the items may be null. 1: public class NullableIntComparer : IComparer<int?> 2: { 3: public int Compare(int? x, int? y) 4: { 5: return (x == null) 6: ? ((y == null) ? 0 : -1) 7: : x.Value.CompareTo(y); 8: } 9: }  Now, if you want a custom sort -- especially on large-grained objects with different possible sort fields -- this is the best option you have.  But if you just want to take advantage of the natural ordering of the type, there is an easier way.  If the type you want to compare already implements IComparable<T> or if the type is System.Nullable<T> where T implements IComparable, there is a class in the System.Collections.Generic namespace called Comparer<T> which exposes a property called Default that will create a singleton that represents the default comparer for items of that type.  For example: 1: // compares integers 2: var intComparer = Comparer<int>.Default; 3:  4: // compares DateTime values 5: var dateTimeComparer = Comparer<DateTime>.Default; 6:  7: // compares nullable doubles using the null rules! 8: var nullableDoubleComparer = Comparer<double?>.Default;  This helps you avoid having to remember the messy null logic and makes it to compare objects where you don’t know if one or more of the values is null. This works especially well when creating say an IComparer<T> implementation for a large-grained class that may or may not contain a field.  For example, let’s say you want to create a sorting comparer for a stock open price, but if the market the stock is trading in hasn’t opened yet, the open price will be null.  We could handle this (assuming a reasonable Quote definition) like: 1: public class Quote 2: { 3: // the opening price of the symbol quoted 4: public double? Open { get; set; } 5:  6: // ticker symbol 7: public string Symbol { get; set; } 8:  9: // etc. 10: } 11:  12: public class OpenPriceQuoteComparer : IComparer<Quote> 13: { 14: // Compares two quotes by opening price 15: public int Compare(Quote x, Quote y) 16: { 17: return Comparer<double?>.Default.Compare(x.Open, y.Open); 18: } 19: } Summary Defining a custom comparer is often needed for non-natural ordering or defining alternative orderings, but when you just want to compare two items that are IComparable<T> and account for null behavior, you can use the Comparer<T>.Default comparer generator and you’ll never have to worry about correct null value sorting again.     Technorati Tags: C#,.NET,Little Wonders,BlackRabbitCoder,IComparable,Comparer

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  • Reasoner Conversion Problems:

    - by Annalyne
    I have this code right here in Java and I wanted to translate it in C++, but I had some problems going: this is the java code: import java.io.*; import java.util.*; public class ClueReasoner { private int numPlayers; private int playerNum; private int numCards; private SATSolver solver; private String caseFile = "cf"; private String[] players = {"sc", "mu", "wh", "gr", "pe", "pl"}; private String[] suspects = {"mu", "pl", "gr", "pe", "sc", "wh"}; private String[] weapons = {"kn", "ca", "re", "ro", "pi", "wr"}; private String[] rooms = {"ha", "lo", "di", "ki", "ba", "co", "bi", "li", "st"}; private String[] cards; public ClueReasoner() { numPlayers = players.length; // Initialize card info cards = new String[suspects.length + weapons.length + rooms.length]; int i = 0; for (String card : suspects) cards[i++] = card; for (String card : weapons) cards[i++] = card; for (String card : rooms) cards[i++] = card; numCards = i; // Initialize solver solver = new SATSolver(); addInitialClauses(); } private int getPlayerNum(String player) { if (player.equals(caseFile)) return numPlayers; for (int i = 0; i < numPlayers; i++) if (player.equals(players[i])) return i; System.out.println("Illegal player: " + player); return -1; } private int getCardNum(String card) { for (int i = 0; i < numCards; i++) if (card.equals(cards[i])) return i; System.out.println("Illegal card: " + card); return -1; } private int getPairNum(String player, String card) { return getPairNum(getPlayerNum(player), getCardNum(card)); } private int getPairNum(int playerNum, int cardNum) { return playerNum * numCards + cardNum + 1; } public void addInitialClauses() { // TO BE IMPLEMENTED AS AN EXERCISE // Each card is in at least one place (including case file). for (int c = 0; c < numCards; c++) { int[] clause = new int[numPlayers + 1]; for (int p = 0; p <= numPlayers; p++) clause[p] = getPairNum(p, c); solver.addClause(clause); } // If a card is one place, it cannot be in another place. // At least one card of each category is in the case file. // No two cards in each category can both be in the case file. } public void hand(String player, String[] cards) { playerNum = getPlayerNum(player); // TO BE IMPLEMENTED AS AN EXERCISE } public void suggest(String suggester, String card1, String card2, String card3, String refuter, String cardShown) { // TO BE IMPLEMENTED AS AN EXERCISE } public void accuse(String accuser, String card1, String card2, String card3, boolean isCorrect) { // TO BE IMPLEMENTED AS AN EXERCISE } public int query(String player, String card) { return solver.testLiteral(getPairNum(player, card)); } public String queryString(int returnCode) { if (returnCode == SATSolver.TRUE) return "Y"; else if (returnCode == SATSolver.FALSE) return "n"; else return "-"; } public void printNotepad() { PrintStream out = System.out; for (String player : players) out.print("\t" + player); out.println("\t" + caseFile); for (String card : cards) { out.print(card + "\t"); for (String player : players) out.print(queryString(query(player, card)) + "\t"); out.println(queryString(query(caseFile, card))); } } public static void main(String[] args) { ClueReasoner cr = new ClueReasoner(); String[] myCards = {"wh", "li", "st"}; cr.hand("sc", myCards); cr.suggest("sc", "sc", "ro", "lo", "mu", "sc"); cr.suggest("mu", "pe", "pi", "di", "pe", null); cr.suggest("wh", "mu", "re", "ba", "pe", null); cr.suggest("gr", "wh", "kn", "ba", "pl", null); cr.suggest("pe", "gr", "ca", "di", "wh", null); cr.suggest("pl", "wh", "wr", "st", "sc", "wh"); cr.suggest("sc", "pl", "ro", "co", "mu", "pl"); cr.suggest("mu", "pe", "ro", "ba", "wh", null); cr.suggest("wh", "mu", "ca", "st", "gr", null); cr.suggest("gr", "pe", "kn", "di", "pe", null); cr.suggest("pe", "mu", "pi", "di", "pl", null); cr.suggest("pl", "gr", "kn", "co", "wh", null); cr.suggest("sc", "pe", "kn", "lo", "mu", "lo"); cr.suggest("mu", "pe", "kn", "di", "wh", null); cr.suggest("wh", "pe", "wr", "ha", "gr", null); cr.suggest("gr", "wh", "pi", "co", "pl", null); cr.suggest("pe", "sc", "pi", "ha", "mu", null); cr.suggest("pl", "pe", "pi", "ba", null, null); cr.suggest("sc", "wh", "pi", "ha", "pe", "ha"); cr.suggest("wh", "pe", "pi", "ha", "pe", null); cr.suggest("pe", "pe", "pi", "ha", null, null); cr.suggest("sc", "gr", "pi", "st", "wh", "gr"); cr.suggest("mu", "pe", "pi", "ba", "pl", null); cr.suggest("wh", "pe", "pi", "st", "sc", "st"); cr.suggest("gr", "wh", "pi", "st", "sc", "wh"); cr.suggest("pe", "wh", "pi", "st", "sc", "wh"); cr.suggest("pl", "pe", "pi", "ki", "gr", null); cr.printNotepad(); cr.accuse("sc", "pe", "pi", "bi", true); } } how can I convert this? there are too many errors I get. for my C++ code (as a commentor asked for) #include <iostream> #include <cstdlib> #include <string> using namespace std; void Scene_Reasoner() { int numPlayer; int playerNum; int cardNum; string filecase = "Case: "; string players [] = {"sc", "mu", "wh", "gr", "pe", "pl"}; string suspects [] = {"mu", "pl", "gr", "pe", "sc", "wh"}; string weapons [] = {"kn", "ca", "re", "ro", "pi", "wr"}; string rooms[] = {"ha", "lo", "di", "ki", "ba", "co", "bi", "li", "st"}; string cards [0]; }; void Scene_Reason_Base () { numPlayer = players.length; // Initialize card info cards = new String[suspects.length + weapons.length + rooms.length]; int i = 0; for (String card : suspects) cards[i++] = card; for (String card : weapons) cards[i++] = card; for (String card : rooms) cards[i++] = card; cardNum = i; }; private int getCardNum (string card) { for (int i = 0; i < numCards; i++) if (card.equals(cards[i])) return i; cout << "Illegal card: " + card <<endl; return -1; }; private int getPairNum(String player, String card) { return getPairNum(getPlayerNum(player), getCardNum(card)); }; private int getPairNum(int playerNum, int cardNum) { return playerNum * numCards + cardNum + 1; }; int main () { return 0; }

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  • Java style FOR loop in a clojure interpeter ?

    - by Kevin
    I have a basic interpreter in clojure. Now i need to implement for (initialisation; finish-test; loop-update) { statements } inside my interpreter. I will attach my interpreter code I got so far. Any help is appreciated. Interpreter (declare interpret make-env) ;; (def do-trace false) ;; ;; simple utilities (def third ; return third item in a list (fn [a-list] (second (rest a-list)))) (def fourth ; return fourth item in a list (fn [a-list] (third (rest a-list)))) (def run ; make it easy to test the interpreter (fn [e] (println "Processing: " e) (println "=> " (interpret e (make-env))))) ;; for the environment (def make-env (fn [] '())) (def add-var (fn [env var val] (cons (list var val) env))) (def lookup-var (fn [env var] (cond (empty? env) 'error (= (first (first env)) var) (second (first env)) :else (lookup-var (rest env) var)))) ;; -- define numbers (def is-number? (fn [expn] (number? expn))) (def interpret-number (fn [expn env] expn)) ;; -- define symbols (def is-symbol? (fn [expn] (symbol? expn))) (def interpret-symbol (fn [expn env] (lookup-var env expn))) ;; -- define boolean (def is-boolean? (fn [expn] (or (= expn 'true) (= expn 'false)))) (def interpret-boolean (fn [expn env] expn)) ;; -- define functions (def is-function? (fn [expn] (and (list? expn) (= 3 (count expn)) (= 'lambda (first expn))))) (def interpret-function (fn [expn env] expn)) ;; -- define addition (def is-plus? (fn [expn] (and (list? expn) (= 3 (count expn)) (= '+ (first expn))))) (def interpret-plus (fn [expn env] (+ (interpret (second expn) env) (interpret (third expn) env)))) ;; -- define subtraction (def is-minus? (fn [expn] (and (list? expn) (= 3 (count expn)) (= '- (first expn))))) (def interpret-minus (fn [expn env] (- (interpret (second expn) env) (interpret (third expn) env)))) ;; -- define multiplication (def is-times? (fn [expn] (and (list? expn) (= 3 (count expn)) (= '* (first expn))))) (def interpret-times (fn [expn env] (* (interpret (second expn) env) (interpret (third expn) env)))) ;; -- define division (def is-divides? (fn [expn] (and (list? expn) (= 3 (count expn)) (= '/ (first expn))))) (def interpret-divides (fn [expn env] (/ (interpret (second expn) env) (interpret (third expn) env)))) ;; -- define equals test (def is-equals? (fn [expn] (and (list? expn) (= 3 (count expn)) (= '= (first expn))))) (def interpret-equals (fn [expn env] (= (interpret (second expn) env) (interpret (third expn) env)))) ;; -- define greater-than test (def is-greater-than? (fn [expn] (and (list? expn) (= 3 (count expn)) (= '> (first expn))))) (def interpret-greater-than (fn [expn env] (> (interpret (second expn) env) (interpret (third expn) env)))) ;; -- define not (def is-not? (fn [expn] (and (list? expn) (= 2 (count expn)) (= 'not (first expn))))) (def interpret-not (fn [expn env] (not (interpret (second expn) env)))) ;; -- define or (def is-or? (fn [expn] (and (list? expn) (= 3 (count expn)) (= 'or (first expn))))) (def interpret-or (fn [expn env] (or (interpret (second expn) env) (interpret (third expn) env)))) ;; -- define and (def is-and? (fn [expn] (and (list? expn) (= 3 (count expn)) (= 'and (first expn))))) (def interpret-and (fn [expn env] (and (interpret (second expn) env) (interpret (third expn) env)))) ;; -- define with (def is-with? (fn [expn] (and (list? expn) (= 3 (count expn)) (= 'with (first expn))))) (def interpret-with (fn [expn env] (interpret (third expn) (add-var env (first (second expn)) (interpret (second (second expn)) env))))) ;; -- define if (def is-if? (fn [expn] (and (list? expn) (= 4 (count expn)) (= 'if (first expn))))) (def interpret-if (fn [expn env] (cond (interpret (second expn) env) (interpret (third expn) env) :else (interpret (fourth expn) env)))) ;; -- define function-application (def is-function-application? (fn [expn env] (and (list? expn) (= 2 (count expn)) (is-function? (interpret (first expn) env))))) (def interpret-function-application (fn [expn env] (let [function (interpret (first expn) env)] (interpret (third function) (add-var env (first (second function)) (interpret (second expn) env)))))) ;; the interpreter itself (def interpret (fn [expn env] (cond do-trace (println "Interpret is processing: " expn)) (cond ; basic values (is-number? expn) (interpret-number expn env) (is-symbol? expn) (interpret-symbol expn env) (is-boolean? expn) (interpret-boolean expn env) (is-function? expn) (interpret-function expn env) ; built-in functions (is-plus? expn) (interpret-plus expn env) (is-minus? expn) (interpret-minus expn env) (is-times? expn) (interpret-times expn env) (is-divides? expn) (interpret-divides expn env) (is-equals? expn) (interpret-equals expn env) (is-greater-than? expn) (interpret-greater-than expn env) (is-not? expn) (interpret-not expn env) (is-or? expn) (interpret-or expn env) (is-and? expn) (interpret-and expn env) ; special syntax (is-with? expn) (interpret-with expn env) (is-if? expn) (interpret-if expn env) ; functions (is-function-application? expn env) (interpret-function-application expn env) :else 'error)))

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  • std::vector optimisation required

    - by marcp
    I've written a routine that uses std::vector<double> rather heavily. It runs rather slowly and AQTime seems to imply that I am constructing mountains of vectors but I'm not sure why I would be. For some context, my sample run iterates 10 times. Each iteration copies 3 c arrays of ~400 points into vectors and creates 3 new same sized vectors for output. Each output point might be the result of summing up to 20 points from 2 of the input vectors, which works out to a worst case of 10*400*3*2*20 = 480,000 dereferences. Incredibly the profiler indicates that some of the std:: methods are being called 46 MILLION times. I suspect I'm doing something wrong! Some code: vector<double>gdbChannel::GetVector() { if (fHaveDoubleData & (fLength > 0)) { double * pD = getDoublePointer(); vector<double>v(pD, pD + fLength); return v; } else { throw(Exception("attempt to retrieve vector on empty line")); ; } } void gdbChannel::SaveVector(GX_HANDLE _hLine, const vector<double> & V) { if (hLine != _hLine) { GetLine(_hLine, V.size(), true); } GX_DOUBLE * pData = getDoublePointer(); memcpy(pData, &V[0], V.size()*sizeof(V[0])); ReplaceData(); } ///This routine gets called 10 times bool SpecRatio::DoWork(GX_HANDLE_PTR pLine) { if (!(hKin.GetLine(*pLine, true) && hUin.GetLine(*pLine, true) && hTHin.GetLine(*pLine, true))) { return true; } vector<double>vK = hKin.GetVector(); vector<double>vU = hUin.GetVector(); vector<double>vTh = hTHin.GetVector(); if ((vK.size() == 0) || (vU.size() == 0) || (vTh.size() == 0)) { return true; } ///TODO: confirm all vectors the same lenghth len = vK.size(); vUK.clear(); // these 3 vectors are declared as private class members vUTh.clear(); vThK.clear(); vUK.reserve(len); vUTh.reserve(len); vThK.reserve(len); // TODO: ensure everything is same fidincr, fidstart and length for (int i = 0; i < len; i++) { if (vK.at(i) < MinK) { vUK.push_back(rDUMMY); vUTh.push_back(rDUMMY); vThK.push_back(rDUMMY); } else { vUK.push_back(RatioPoint(vU, vK, i, UMin, KMin)); vUTh.push_back(RatioPoint(vU, vTh, i, UMin, ThMin)); vThK.push_back(RatioPoint(vTh, vK, i, ThMin, KMin)); } } hUKout.setFidParams(hKin); hUKout.SaveVector(*pLine, vUK); hUTHout.setFidParams(hKin); hUTHout.SaveVector(*pLine, vUTh); hTHKout.setFidParams(hKin); hTHKout.SaveVector(*pLine, vThK); return TestError(); } double SpecRatio::VValue(vector<double>V, int Index) { double result; if ((Index < 0) || (Index >= len)) { result = 0; } else { try { result = V.at(Index); if (OasisUtils::isDummy(result)) { result = 0; } } catch (out_of_range) { result = 0; } } return result; } double SpecRatio::RatioPoint(vector<double>Num, vector<double>Denom, int Index, double NumMin, double DenomMin) { double num = VValue(Num, Index); double denom = VValue(Denom, Index); int s = 0; // Search equalled 10 in this case while (((num < NumMin) || (denom < DenomMin)) && (s < Search)) { num += VValue(Num, Index - s) + VValue(Num, Index + s); denom += VValue(Denom, Index - s) + VValue(Denom, Index + s); s++; } if ((num < NumMin) || (denom < DenomMin)) { return rDUMMY; } else { return num / denom; } } The top AQTime offenders are: std::_Uninit_copy , double *, std::allocator 3.65 secs and 115731 Hits std::_Construct 1.69 secs and 46450637 Hits std::_Vector_const_iterator ::operator !=1.66 secs and 46566395 Hits and so on... std::allocator<double>::construct, operator new, std::_Vector_const_iterator<double, std::allocator<double> >::operator ++, std::_Vector_const_iterator<double, std::allocator<double> >::operator * std::_Vector_const_iterator<double, std::allocator<double> >::operator == each get called over 46 million times. I'm obviously doing something wrong to cause all these objects to be created. Can anyone see my error(s)?

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  • Adapting non-iterable containers to be iterated via custom templatized iterator

    - by DAldridge
    I have some classes, which for various reasons out of scope of this discussion, I cannot modify (irrelevant implementation details omitted): class Foo { /* ... irrelevant public interface ... */ }; class Bar { public: Foo& get_foo(size_t index) { /* whatever */ } size_t size_foo() { /* whatever */ } }; (There are many similar 'Foo' and 'Bar' classes I'm dealing with, and it's all generated code from elsewhere and stuff I don't want to subclass, etc.) [Edit: clarification - although there are many similar 'Foo' and 'Bar' classes, it is guaranteed that each "outer" class will have the getter and size methods. Only the getter method name and return type will differ for each "outer", based on whatever it's "inner" contained type is. So, if I have Baz which contains Quux instances, there will be Quux& Baz::get_quux(size_t index), and size_t Baz::size_quux().] Given the design of the Bar class, you cannot easily use it in STL algorithms (e.g. for_each, find_if, etc.), and must do imperative loops rather than taking a functional approach (reasons why I prefer the latter is also out of scope for this discussion): Bar b; size_t numFoo = b.size_foo(); for (int fooIdx = 0; fooIdx < numFoo; ++fooIdx) { Foo& f = b.get_foo(fooIdx); /* ... do stuff with 'f' ... */ } So... I've never created a custom iterator, and after reading various questions/answers on S.O. about iterator_traits and the like, I came up with this (currently half-baked) "solution": First, the custom iterator mechanism (NOTE: all uses of 'function' and 'bind' are from std::tr1 in MSVC9): // Iterator mechanism... template <typename TOuter, typename TInner> class ContainerIterator : public std::iterator<std::input_iterator_tag, TInner> { public: typedef function<TInner& (size_t)> func_type; ContainerIterator(const ContainerIterator& other) : mFunc(other.mFunc), mIndex(other.mIndex) {} ContainerIterator& operator++() { ++mIndex; return *this; } bool operator==(const ContainerIterator& other) { return ((mFunc.target<TOuter>() == other.mFunc.target<TOuter>()) && (mIndex == other.mIndex)); } bool operator!=(const ContainerIterator& other) { return !(*this == other); } TInner& operator*() { return mFunc(mIndex); } private: template<typename TOuter, typename TInner> friend class ContainerProxy; ContainerIterator(func_type func, size_t index = 0) : mFunc(func), mIndex(index) {} function<TInner& (size_t)> mFunc; size_t mIndex; }; Next, the mechanism by which I get valid iterators representing begin and end of the inner container: // Proxy(?) to the outer class instance, providing a way to get begin() and end() // iterators to the inner contained instances... template <typename TOuter, typename TInner> class ContainerProxy { public: typedef function<TInner& (size_t)> access_func_type; typedef function<size_t ()> size_func_type; typedef ContainerIterator<TOuter, TInner> iter_type; ContainerProxy(access_func_type accessFunc, size_func_type sizeFunc) : mAccessFunc(accessFunc), mSizeFunc(sizeFunc) {} iter_type begin() const { size_t numItems = mSizeFunc(); if (0 == numItems) return end(); else return ContainerIterator<TOuter, TInner>(mAccessFunc, 0); } iter_type end() const { size_t numItems = mSizeFunc(); return ContainerIterator<TOuter, TInner>(mAccessFunc, numItems); } private: access_func_type mAccessFunc; size_func_type mSizeFunc; }; I can use these classes in the following manner: // Sample function object for taking action on an LMX inner class instance yielded // by iteration... template <typename TInner> class SomeTInnerFunctor { public: void operator()(const TInner& inner) { /* ... whatever ... */ } }; // Example of iterating over an outer class instance's inner container... Bar b; /* assume populated which contained items ... */ ContainerProxy<Bar, Foo> bProxy( bind(&Bar::get_foo, b, _1), bind(&Bar::size_foo, b)); for_each(bProxy.begin(), bProxy.end(), SomeTInnerFunctor<Foo>()); Empirically, this solution functions correctly (minus any copy/paste or typos I may have introduced when editing the above for brevity). So, finally, the actual question: I don't like requiring the use of bind() and _1 placeholders, etcetera by the caller. All they really care about is: outer type, inner type, outer type's method to fetch inner instances, outer type's method to fetch count inner instances. Is there any way to "hide" the bind in the body of the template classes somehow? I've been unable to find a way to separately supply template parameters for the types and inner methods separately... Thanks! David

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  • So No TECH job so far.

    - by Ratman21
    O I found some temp work for the US Census and I have managed to keep the house (so far) but, it looks like I/we are going to have to do a short sale and the temp job will be ending soon.   On top of that it looks like the unemployment fund for me is drying up. I will have about one month left after the Census job is done. I am now down to Appling for work at the KFC.   This is type a work I started with, before I was a tech geek and really I didn’t think I would be doing this kind of work in my later years but, I have a wife and kid. So I got to suck it up and do it.   Oh and here is my new resume…go ahead I know you want to tare it up. I really don’t care any more.   Scott L. Newman 45219 Dutton Way, Callahan, FL32011 H: (904)879-4880 C: (352)356-0945 E: [email protected] Web:  http://beingscottnewman.webs.com/                                                       ______                                                                                 OBJECTIVE To obtain a Network or Technical support position     KEYWORD SUMMARY CompTIA A+, Network+, and Security+ Certified., Network Operation, Technical Support, Client/Vendor Relations, Networking/Administration, Cisco Routers/Switches, Helpdesk, Microsoft Office Suite, Website Design/Dev./Management, Frame Relay, ISDN, Windows NT/98/XP, Visio, Inventory Management, CICS, Programming, COBOL IV, Assembler, RPG   QUALIFICATIONS SUMMARY Twenty years’ experience in computer operations, technical support, and technical writing. Also have two and half years’ experience in internet / intranet operations.   PROFESSIONAL EXPERIENCE October 2009 – Present*   Volunteer Web site and PC technician – Part time       True Faith Christian Fellowship Church – Callahan, FL, Project: Create and maintain web site for Church to give it a worldwide exposure Aug 2008 – September 2009:* Volunteer Church sound and video technician – Part time      Thomas Creek Baptist Church – Callahan, FL   *Note Jobs were for the learning and/or keeping updated on skills, while looking for a tech job and training for new skills.   February 2005 to October 2008: Client Server Dev/Analyst I, Fidelity National Information Services, Jacksonville, FL (FNIS acquired Certegy in 2005 and out of 20 personal, was one of three kept on.) August 2003 to February 2005: Senior NetOps Operator, Certegy, St.Pete, Fl. (August 2003, Certegy terminated contract with EDS and out of 40 personal, was one of six kept on.) Projects: Creation and update of listing and placement for all raised floor equipment at St.Pete site. Listing was made up of, floor plan of the raised floor and equipment racks diagrams showing the placement of all devices using Visio. This was cross-referenced with an inventory excel document showing what dept was responsible for each device. Sole creator of Network operation and Server Operation procedures guide (NetOps Guide).  Expertise: Resolving circuit and/or router issues or assist circuit carrier in resolving issue from the company Network Operation Center (NOC). As well as resolving application problems or assist application support in resolution of it.     July 1999 to August 2003: Senior NetOps Operator,EDS (Certegy Account), St.Pete, FL Same expertise and on going projects as listed above for FNIS/Certegy. (Equifax outsourced the NetOps dept. to EDS in 1999)         January 1991 to July 1999: NetOps/Tandem Operator, Equifax, St.Pete & Tampa, FL Same as all of the above for FNIS/Certegy/EDS except for circuit and router issues   EDUCATION ? New Horizons Computer Learning Center, Jacksonville, Florida - CompTIA A+, Security+, and     Network+ Certified.                        Currently working on CCNA Certification 07/30/10 ? Mott Community College, Flint, Michigan – Associates Degree - Data Processing and General Education ? Currently studying Japanese

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  • Types of semantic bugs, logic errors [closed]

    - by C-Otto
    I am a PhD student and currently focus on automatically finding instances of new types of bugs in (Java) programs that cannot be found by existing tools like FindBugs. The existing tool currently is used to prove/disprove termination of (Java) programs. I have some ideas (see below), but I could need more input from you (experienced programmers, potential users of my tool). What kind of bugs do you wish to find? What types of bugs exist and might be suitable for my analysis? One strength of the approach I use is detailled information about the heap. So in contrast to FindBugs, I can work with knowledge of the form "variable x and variable y are disjoint on the heap" or "variable z is not cyclic". It is also possible to see if a method might have side effects (and if so, which variables may/may not be affected by it). Example 1: Vacuous call: Graph graphOne = createGraph(); Graph graphTwo = createGraph(); Node source = graphTwo.getRootNode(); for (Node n : graphOne.getNodes()) { if (areConnected(source, n)) { graphTwo.addNode(n); } } Imagine createGraph() creates a fresh graph, so that graphOne and graphTwo are disjoint on the heap. Then, because source is taken from graphTwo instead of graphOne, the call to areConnected always returns false. In this situation I could find out that the call areConnected is useless (because it does not have any side effect and the return value always is false) which helps finding the real bug (taking source from the wrong graph). For this the information that x and y are disjoint (because graphOne and graphTwo are disjoint) is crucial. This bug is related to calling x.equals(y) where x and y are objects of different classes. In this scenario, most implementations of equals() always return false, which most likely is not the intended result. FindBugs already finds this bug (hardcoded to equals(), semantics of implementation is not checked). Example 2: Useless code: someCode(); while (something()) { yetMoreSomething(); } moreCode(); In the case that the loop (so the code in something() and yetMoreSomething()) does not modify anything visible outside the loop, it does not make sense to run this code - the program has the same behaviour as someCode(); moreCode() (i.e., without the loop). To find this out, one needs detailled information about the side effects of the (possibly useless) code. If I can prove that the code does not have any side effect that can be observed afterwards (in the example: in moreCode() or later), then the code indeed is useless. Of course, here Input/Output of any form must be seen as a side effect, so that a System.out.println(...) is not considered useless. Example 3: Ignored return value: Instead of x = foo(); and making use of x, the method is called without storing the result: foo();. If the method does not have any side effect, its invocation is useless and can be dropped. Most likely, the bug here is that the returned value should have been used. Here, too, detailled information about side effects are needed. Can you think of similar types of bugs that might be detected (only) with detailled information about the heap, side effects, semantics of called methods, ...? Did you encounter bugs related to the ones shown below in "real life"? By the way, the tool is AProVE and Java related publications can be found on my homepage. Thanks a lot, Carsten

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  • SQL Server: Writing CASE expressions properly when NULLs are involved

    - by Mladen Prajdic
    We’ve all written a CASE expression (yes, it’s an expression and not a statement) or two every now and then. But did you know there are actually 2 formats you can write the CASE expression in? This actually bit me when I was trying to add some new functionality to an old stored procedure. In some rare cases the stored procedure just didn’t work correctly. After a quick look it turned out to be a CASE expression problem when dealing with NULLS. In the first format we make simple “equals to” comparisons to a value: SELECT CASE <value> WHEN <equals this value> THEN <return this> WHEN <equals this value> THEN <return this> -- ... more WHEN's here ELSE <return this> END Second format is much more flexible since it allows for complex conditions. USE THIS ONE! SELECT CASE WHEN <value> <compared to> <value> THEN <return this> WHEN <value> <compared to> <value> THEN <return this> -- ... more WHEN's here ELSE <return this> END Now that we know both formats and you know which to use (the second one if that hasn’t been clear enough) here’s an example how the first format WILL make your evaluation logic WRONG. Run the following code for different values of @i. Just comment out any 2 out of 3 “SELECT @i =” statements. DECLARE @i INTSELECT  @i = -1 -- first resultSELECT  @i = 55 -- second resultSELECT  @i = NULL -- third resultSELECT @i AS OriginalValue, -- first CASE format. DON'T USE THIS! CASE @i WHEN -1 THEN '-1' WHEN NULL THEN 'We have a NULL!' ELSE 'We landed in ELSE' END AS DontUseThisCaseFormatValue, -- second CASE format. USE THIS! CASE WHEN @i = -1 THEN '-1' WHEN @i IS NULL THEN 'We have a NULL!' ELSE 'We landed in ELSE' END AS UseThisCaseFormatValue When the value of @i is –1 everything works as expected, since both formats go into the –1 WHEN branch. When the value of @i is 55 everything again works as expected, since both formats go into the ELSE branch. When the value of @i is NULL the problems become evident. The first format doesn’t go into the WHEN NULL branch because it makes an equality comparison between two NULLs. Because a NULL is an unknown value: NULL = NULL is false. That is why the first format goes into the ELSE Branch but the second format correctly handles the proper IS NULL comparison.   Please use the second more explicit format. Your future self will be very grateful to you when he doesn’t have to discover these kinds of bugs.

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  • Hidden Features of C#?

    - by Serhat Özgel
    This came to my mind after I learned the following from this question: where T : struct We, C# developers, all know the basics of C#. I mean declarations, conditionals, loops, operators, etc. Some of us even mastered the stuff like Generics, anonymous types, lambdas, linq, ... But what are the most hidden features or tricks of C# that even C# fans, addicts, experts barely know? Here are the revealed features so far: Keywords yield by Michael Stum var by Michael Stum using() statement by kokos readonly by kokos as by Mike Stone as / is by Ed Swangren as / is (improved) by Rocketpants default by deathofrats global:: by pzycoman using() blocks by AlexCuse volatile by Jakub Šturc extern alias by Jakub Šturc Attributes DefaultValueAttribute by Michael Stum ObsoleteAttribute by DannySmurf DebuggerDisplayAttribute by Stu DebuggerBrowsable and DebuggerStepThrough by bdukes ThreadStaticAttribute by marxidad FlagsAttribute by Martin Clarke ConditionalAttribute by AndrewBurns Syntax ?? operator by kokos number flaggings by Nick Berardi where T:new by Lars Mæhlum implicit generics by Keith one-parameter lambdas by Keith auto properties by Keith namespace aliases by Keith verbatim string literals with @ by Patrick enum values by lfoust @variablenames by marxidad event operators by marxidad format string brackets by Portman property accessor accessibility modifiers by xanadont ternary operator (?:) by JasonS checked and unchecked operators by Binoj Antony implicit and explicit operators by Flory Language Features Nullable types by Brad Barker Currying by Brian Leahy anonymous types by Keith __makeref __reftype __refvalue by Judah Himango object initializers by lomaxx format strings by David in Dakota Extension Methods by marxidad partial methods by Jon Erickson preprocessor directives by John Asbeck DEBUG pre-processor directive by Robert Durgin operator overloading by SefBkn type inferrence by chakrit boolean operators taken to next level by Rob Gough pass value-type variable as interface without boxing by Roman Boiko programmatically determine declared variable type by Roman Boiko Static Constructors by Chris Easier-on-the-eyes / condensed ORM-mapping using LINQ by roosteronacid Visual Studio Features select block of text in editor by Himadri snippets by DannySmurf Framework TransactionScope by KiwiBastard DependantTransaction by KiwiBastard Nullable<T> by IainMH Mutex by Diago System.IO.Path by ageektrapped WeakReference by Juan Manuel Methods and Properties String.IsNullOrEmpty() method by KiwiBastard List.ForEach() method by KiwiBastard BeginInvoke(), EndInvoke() methods by Will Dean Nullable<T>.HasValue and Nullable<T>.Value properties by Rismo GetValueOrDefault method by John Sheehan Tips & Tricks nice method for event handlers by Andreas H.R. Nilsson uppercase comparisons by John access anonymous types without reflection by dp a quick way to lazily instantiate collection properties by Will JavaScript-like anonymous inline-functions by roosteronacid Other netmodules by kokos LINQBridge by Duncan Smart Parallel Extensions by Joel Coehoorn

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  • Scaling gwt's "Contacts" (sample project) AppController with MVP

    - by brad
    I'm just learning GWT so I'm still trying to sort out all of its quirks and features. I'm reading through the example they give illustrating the MVP pattern, and I pretty much get it, except I'm wondering about one thing. The AppController they use implements the ValueChangeHandler interface and the onValueChange method is triggered when history changes. My problem is with this onValueChange in the AppController (i've included it below for anyone who hasn't seen the sample project). It's doing a string comparison on the history token sent in and instantiating the appropriate presenter to handle the action. This is all fine and dandy for the sample app with 3 actions, but how would one scale this to a real app with many more actions? Sticking to this pattern would lead to a pretty large/ugly else if, but I'm still too new to GWT (and java) to infer a better pattern for larger apps. Any help is greatly appreciated! public class AppController implements Presenter, ValueChangeHandler<String> { ... public void onValueChange(ValueChangeEvent<String> event) { String token = event.getValue(); if (token != null) { Presenter presenter = null; if (token.equals("list")) { presenter = new ContactsPresenter(rpcService, eventBus, new ContactsView()); } else if (token.equals("add")) { presenter = new EditContactPresenter(rpcService, eventBus, new EditContactView()); } else if (token.equals("edit")) { presenter = new EditContactPresenter(rpcService, eventBus, new EditContactView()); } if (presenter != null) { presenter.go(container); } } } }

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  • Error C2451: Illegal conditional expression of type 'UnaryOp<E1, Op>' in ostream - visual studio 9

    - by Steven Hill
    I am getting a repeated error with VS 9. The code compiles under GNU C++, but I want debug with the VS IDE. Any idea what could be causing this error. Error 13 error C2451: conditional expression of type 'UnaryOp' is illegal \Microsoft Visual Studio 9.0\VC\include\ostream 512 //unary constraint template class UnaryOp : public Constraint { public: const E1& e1; UnaryOp(const E1& _e1); bool Satisfiable() const; Bool SatisfiableAux() const; void Print (std::ostream& os) const; UnaryOp* clone () const; //operator bool () const { return true; } }; template std::ostream& operator<<(std::ostream& os, const UnaryOp& unop); UnaryOp code that uses ostream: template INLINE void UnaryOp::Print (std::ostream& os) const { os << *this; } template INLINE std::ostream& operator<<(std::ostream& os, const UnaryOp& unop) { return os << Op::name << unop.e1; } ostream line with error: _Myt& __CLR_OR_THIS_CALL put(_Elem _Ch) { // insert a character ios_base::iostate _State = ios_base::goodbit; const sentry _Ok(*this); 512 if (!_Ok) _State |= ios_base::badbit; else { // state okay, insert character _TRY_IO_BEGIN

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  • Jasper report exports empty data in PDF format when there is more data

    - by stanley
    I have a report to be exported in excel, pdf and word using jasper reports. I use xml file as the DataSource for the report, but when the data increases jasper report exports empty file in only for PDF format, when i reduce the data content it export the data available correctly. is there any limitation to pdf size? , how can we manage the size in jasper reports from java? My jrxml is really big, so i cannot add it here, i have added my java code which i use to export the content:- JRAbstractExporter exporter = null; if (format.equals("pdf")) { exporter = new JRPdfExporter(); jasperPrint.setPageWidth(Integer.parseInt( pWidth )); } else if (format.equals("xls")) { exporter = new JRXlsExporter(); } else if (format.equals("doc")) { jasperPrint.setPageWidth(Integer.parseInt( pWidth )); } exporter.setParameter(JRExporterParameter.JASPER_PRINT, jasperPrint); exporter.setParameter(JRExporterParameter.OUTPUT_STREAM, outputStream_); exporter.exportReport(); contents = outputStream_.toByteArray(); response.setContentType("application/"+format); response.addHeader("Content-disposition", "attachment;filename=" + name.toString() + "."+format);

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