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  • Confused Why I am getting C1010 error?

    - by bluepixel
    I have three files: Main, slist.h and slist.cpp can be seen at http://forums.devarticles.com/c-c-help-52/confused-why-i-am-getting-c2143-and-c1010-error-259574.html I'm trying to make a program where main reads the list of student names from a file (roster.txt) and inserts all the names in a list in ascending order. This is the full class roster list (notCheckedIN). From here I will read all students who have come to write the exams, each checkin will transfer their name to another list (in ascending order) called present. The final product is notCheckedIN will contain a list of all those students that did not write the exam and present will contain the list of all students who wrote the exam Main File: // Exam.cpp : Defines the entry point for the console application. #include "stdafx.h" #include "iostream" #include "iomanip" #include "fstream" #include "string" #include "slist.h" using namespace std; void OpenFile(ifstream&); void GetClassRoster(SortList&, ifstream&); void InputStuName(SortList&, SortList&); void UpdateList(SortList&, SortList&, string); void Print(SortList&, SortList&); const string END_DATA = "EndData"; int main() { ifstream roster; SortList notCheckedIn; //students present SortList present; //student absent OpenFile(roster); if(!roster) //Make sure file is opened return 1; GetClassRoster(notCheckedIn, roster); //insert the roster list into the notCheckedIn list InputStuName(present, notCheckedIn); Print(present, notCheckedIn); return 0; } void OpenFile(ifstream& roster) //Precondition: roster is pointing to file containing student anmes //Postcondition:IF file does not exist -> exit { string fileName = "roster.txt"; roster.open(fileName.c_str()); if(!roster) cout << "***ERROR CANNOT OPEN FILE :"<< fileName << "***" << endl; } void GetClassRoster(SortList& notCheckedIN, ifstream& roster) //Precondition:roster points to file containing list of student last name // && notCheckedIN is empty //Postcondition:notCheckedIN is filled with the names taken from roster.txt in ascending order { string name; roster >> name; while(roster) { notCheckedIN.Insert(name); roster >> name; } } void InputStuName(SortList& present, SortList& notCheckedIN) //Precondition: present list is empty initially and notCheckedIN list is full //Postcondition: repeated prompting to enter stuName // && notCheckedIN will delete all names found in present // && present will contain names present // && names not found in notCheckedIN will report Error { string stuName; cout << "Enter last name (Enter EndData if none to Enter): "; cin >> stuName; while(stuName!=END_DATA) { UpdateList(present, notCheckedIN, stuName); } } void UpdateList(SortList& present, SortList& notCheckedIN, string stuName) //Precondition:stuName is assigned //Postcondition:IF stuName is present, stuName is inserted in present list // && stuName is removed from the notCheckedIN list // ELSE stuName does not exist { if(notCheckedIN.isPresent(stuName)) { present.Insert(stuName); notCheckedIN.Delete(stuName); } else cout << "NAME IS NOT PRESENT" << endl; } void Print(SortList& present, SortList& notCheckedIN) //Precondition: present and notCheckedIN contains a list of student Names present/not present //Postcondition: content of present and notCheckedIN is printed { cout << "Candidates Present" << endl; present.Print(); cout << "Candidates Absent" << endl; notCheckedIN.Print(); } Header File: //Specification File: slist.h //This file gives the specifications of a list abstract data type //List items inserted will be in order //Class SortList, structured type used to represent an ADT using namespace std; const int MAX_LENGTH = 200; typedef string ItemType; //Class Object (class instance) SortList. Variable of class type. class SortList { //Class Member - components of a class, can be either data or functions public: //Constructor //Post-condition: Empty list is created SortList(); //Const member function. Compiler error occurs if any statement within tries to modify a private data bool isEmpty() const; //Post-condition: == true if list is empty // == false if list is not empty bool isFull() const; //Post-condition: == true if list is full // == false if list is full int Length() const; //Post-condition: size of list void Insert(ItemType item); //Precondition: NOT isFull() && item is assigned //Postcondition: item is in list && Length() = Length()@entry + 1 void Delete(ItemType item); //Precondition: NOT isEmpty() && item is assigned //Postcondition: // IF items is in list at entry // first occurance of item in list is removed // && Length() = Length()@entry -1; // ELSE // list is not changed bool isPresent(ItemType item) const; //Precondition: item is assigned //Postcondition: == true if item is present in list // == false if item is not present in list void Print() const; //Postcondition: All component of list have been output private: int length; ItemType data[MAX_LENGTH]; void BinSearch(ItemType, bool&, int&) const; }; Source File: //Implementation File: slist.cpp //This file gives the specifications of a list abstract data type //List items inserted will be in order //Class SortList, structured type used to represent an ADT #include "iostream" #include "slist.h" using namespace std; // int length; // ItemType data[MAX_SIZE]; //Class Object (class instance) SortList. Variable of class type. SortList::SortList() //Constructor //Post-condition: Empty list is created { length=0; } //Const member function. Compiler error occurs if any statement within tries to modify a private data bool SortList::isEmpty() const //Post-condition: == true if list is empty // == false if list is not empty { return(length==0); } bool SortList::isFull() const //Post-condition: == true if list is full // == false if list is full { return (length==(MAX_LENGTH-1)); } int SortList::Length() const //Post-condition: size of list { return length; } void SortList::Insert(ItemType item) //Precondition: NOT isFull() && item is assigned //Postcondition: item is in list && Length() = Length()@entry + 1 // && list componenet are in ascending order of value { int index; index = length -1; while(index >=0 && item<data[index]) { data[index+1]=data[index]; index--; } data[index+1]=item; length++; } void SortList:elete(ItemType item) //Precondition: NOT isEmpty() && item is assigned //Postcondition: // IF items is in list at entry // first occurance of item in list is removed // && Length() = Length()@entry -1; // && list components are in ascending order // ELSE data array is unchanged { bool found; int position; BinSearch(item,found,position); if (found) { for(int index = position; index < length; index++) data[index]=data[index+1]; length--; } } bool SortList::isPresent(ItemType item) const //Precondition: item is assigned && length <= MAX_LENGTH && items are in ascending order //Postcondition: true if item is found in the list // false if item is not found in the list { bool found; int position; BinSearch(item,found,position); return (found); } void SortList::Print() const //Postcondition: All component of list have been output { for(int x= 0; x<length; x++) cout << data[x] << endl; } void SortList::BinSearch(ItemType item, bool found, int position) const //Precondition: item contains item to be found // && item in the list is an ascending order //Postcondition: IF item is in list, position is returned // ELSE item does not exist in the list { int first = 0; int last = length -1; int middle; found = false; while(!found) { middle = (first+last)/2; if(data[middle]<item) first = middle+1; else if (data[middle] > item) last = middle -1; else found = true; } if(found) position = middle; } I cannot get rid of the C1010 error: fatal error C1010: unexpected end of file while looking for precompiled header. Did you forget to add '#include "stdafx.h"' to your source? Is there a way to get rid of this error? When I included "stdafx.h" I received the following 32 errors (which does not make sense to me why because I referred back to my manual on how to use Class method - everything looks a.ok.) Error 1 error C2871: 'std' : a namespace with this name does not exist c:\..\slist.h 6 Error 2 error C2146: syntax error : missing ';' before identifier 'ItemType' c:\..\slist.h 8 Error 3 error C4430: missing type specifier - int assumed. Note: C++ does not support default-int c:\..\slist.h 8 Error 4 error C4430: missing type specifier - int assumed. Note: C++ does not support default-int c:\..\slist.h 8 Error 5 error C2061: syntax error : identifier 'ItemType' c:\..\slist.h 30 Error 6 error C2061: syntax error : identifier 'ItemType' c:\..\slist.h 34 Error 7 error C2061: syntax error : identifier 'ItemType' c:\..\slist.h 43 Error 8 error C2146: syntax error : missing ';' before identifier 'data' c:\..\slist.h 52 Error 9 error C4430: missing type specifier - int assumed. Note: C++ does not support default-int c:\..\slist.h 52 Error 10 error C4430: missing type specifier - int assumed. Note: C++ does not support default-int c:\..\slist.h 52 Error 11 error C2061: syntax error : identifier 'ItemType' c:\..\slist.h 53 Error 12 error C2146: syntax error : missing ')' before identifier 'item' c:\..\slist.cpp 41 Error 13 error C2761: 'void SortList::Insert(void)' : member function redeclaration not allowed c:\..\slist.cpp 41 Error 14 error C2059: syntax error : ')' c:\..\slist.cpp 41 Error 15 error C2143: syntax error : missing ';' before '{' c:\..\slist.cpp 45 Error 16 error C2447: '{' : missing function header (old-style formal list?) c:\..\slist.cpp 45 Error 17 error C2146: syntax error : missing ')' before identifier 'item' c:\..\slist.cpp 57 Error 18 error C2761: 'void SortList:elete(void)' : member function redeclaration not allowed c:\..\slist.cpp 57 Error 19 error C2059: syntax error : ')' c:\..\slist.cpp 57 Error 20 error C2143: syntax error : missing ';' before '{' c:\..\slist.cpp 65 Error 21 error C2447: '{' : missing function header (old-style formal list?) c:\..\slist.cpp 65 Error 22 error C2146: syntax error : missing ')' before identifier 'item' c:\..\slist.cpp 79 Error 23 error C2761: 'bool SortList::isPresent(void) const' : member function redeclaration not allowed c:\..\slist.cpp 79 Error 24 error C2059: syntax error : ')' c:\..\slist.cpp 79 Error 25 error C2143: syntax error : missing ';' before '{' c:\..\slist.cpp 83 Error 26 error C2447: '{' : missing function header (old-style formal list?) c:\..\slist.cpp 83 Error 27 error C2065: 'data' : undeclared identifier c:\..\slist.cpp 95 Error 28 error C2146: syntax error : missing ')' before identifier 'item' c:\..\slist.cpp 98 Error 29 error C2761: 'void SortList::BinSearch(void) const' : member function redeclaration not allowed c:\..\slist.cpp 98 Error 30 error C2059: syntax error : ')' c:\..\slist.cpp 98 Error 31 error C2143: syntax error : missing ';' before '{' c:\..\slist.cpp 103 Error 32 error C2447: '{' : missing function header (old-style formal list?) c:\..\slist.cpp 103

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  • Best Design Pattern for Coupling User Interface Components and Data Structures

    - by szahn
    I have a windows desktop application with a tree view. Due to lack of a sound data-binding solution for a tree view, I've implemented my own layer of abstraction on it to bind nodes to my own data structure. The requirements are as follows: Populate a tree view with nodes that resemble fields in a data structure. When a node is clicked, display the appropriate control to modify the value of that property in the instance of the data structure. The tree view is populated with instances of custom TreeNode classes that inherit from TreeNode. The responsibility of each custom TreeNode class is to (1) format the node text to represent the name and value of the associated field in my data structure, (2) return the control used to modify the property value, (3) get the value of the field in the control (3) set the field's value from the control. My custom TreeNode implementation has a property called "Control" which retrieves the proper custom control in the form of the base control. The control instance is stored in the custom node and instantiated upon first retrieval. So each, custom node has an associated custom control which extends a base abstract control class. Example TreeNode implementation: //The Tree Node Base Class public abstract class TreeViewNodeBase : TreeNode { public abstract CustomControlBase Control { get; } public TreeViewNodeBase(ExtractionField field) { UpdateControl(field); } public virtual void UpdateControl(ExtractionField field) { Control.UpdateControl(field); UpdateCaption(FormatValueForCaption()); } public virtual void SaveChanges(ExtractionField field) { Control.SaveChanges(field); UpdateCaption(FormatValueForCaption()); } public virtual string FormatValueForCaption() { return Control.FormatValueForCaption(); } public virtual void UpdateCaption(string newValue) { this.Text = Caption; this.LongText = newValue; } } //The tree node implementation class public class ExtractionTypeNode : TreeViewNodeBase { private CustomDropDownControl control; public override CustomControlBase Control { get { if (control == null) { control = new CustomDropDownControl(); control.label1.Text = Caption; control.comboBox1.Items.Clear(); control.comboBox1.Items.AddRange( Enum.GetNames( typeof(ExtractionField.ExtractionType))); } return control; } } public ExtractionTypeNode(ExtractionField field) : base(field) { } } //The custom control base class public abstract class CustomControlBase : UserControl { public abstract void UpdateControl(ExtractionField field); public abstract void SaveChanges(ExtractionField field); public abstract string FormatValueForCaption(); } //The custom control generic implementation (view) public partial class CustomDropDownControl : CustomControlBase { public CustomDropDownControl() { InitializeComponent(); } public override void UpdateControl(ExtractionField field) { //Nothing to do here } public override void SaveChanges(ExtractionField field) { //Nothing to do here } public override string FormatValueForCaption() { //Nothing to do here return string.Empty; } } //The custom control specific implementation public class FieldExtractionTypeControl : CustomDropDownControl { public override void UpdateControl(ExtractionField field) { comboBox1.SelectedIndex = comboBox1.FindStringExact(field.Extraction.ToString()); } public override void SaveChanges(ExtractionField field) { field.Extraction = (ExtractionField.ExtractionType) Enum.Parse(typeof(ExtractionField.ExtractionType), comboBox1.SelectedItem.ToString()); } public override string FormatValueForCaption() { return string.Empty; } The problem is that I have "generic" controls which inherit from CustomControlBase. These are just "views" with no logic. Then I have specific controls that inherit from the generic controls. I don't have any functions or business logic in the generic controls because the specific controls should govern how data is associated with the data structure. What is the best design pattern for this?

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  • How do you kill a process tree in linux?

    - by itsadok
    Sometimes, sending a SIGTERM to a process will cause it to send SIGTERM to all its child processes. However, sometimes this doesn't work. Is there a command or a utility that will allow me to kill a process and all its child processes at the same time? I usually resort to manually collecting all the pids into one kill command, but it feels stupid. This SO question asks how to do this with perl, but anything that gets the job done would be great.

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  • Call For Papers Tips and Tricks

    - by speakjava
    This year's JavaOne session review has just been completed and by now everyone who submitted papers should know whether they were successful or not.  I had the pleasure again this year of leading the review of the 'JavaFX and Rich User Experiences' track.  I thought it would be useful to write up a few comments to help people in future when submitting session proposals, not just for JavaOne, but for any of the many developer conferences that run around the world throughout the year.  This also draws on conversations I recently had with various Java User Group leaders at the Oracle User Group summit in Riga.  Many of these leaders run some of the biggest and most successful Java conferences in Europe. Try to think of a title which will sound interesting.  For example, "Experiences of performance tuning embedded Java for an ARM architecture based single board computer" probably isn't going to get as much attention as "Do you like coffee with your dessert? Java on the Raspberry Pi".  When thinking of the subject and title for your talk try to steer clear of sessions that might be too generic (and so get lost in a group of similar sessions).  Introductory talks are great when the audience is new to a subject, but beware of providing sessions that are too basic when the technology has been around for a while and there are lots of tutorials already available on the web. JavaOne, like many other conferences has a number of fields that need to be filled in when submitting a paper.  Many of these are selected from pull-down lists (like which track the session is applicable to).  Check these lists carefully.  A number of sessions we had needed to be shuffled between tracks when it was thought that the one selected was not appropriate.  We didn't count this against any sessions, but it's always a good idea to try and get the right one from the start, just in case. JavaOne, again like many other conferences, has two fields that describe the session being submitted: abstract and summary.  These are the most critical to a successful submission.  The two fields have different names and that is significant; a frequent mistake people make is to write an abstract for a session and then duplicate it for the summary.  The abstract (at least in the case of JavaOne) is what gets printed in the show guide and is typically what will be used by attendees when deciding what sessions to attend.  This is where you need to sell your session, not just to the reviewers, but also the people who you want in your audience.  Submitting a one line abstract (unless it's a really good one line) is not usually enough to decide whether this is worth investing an hour of conference time.  The abstract typically has a limit of a few hundred characters.  Try to use as many of them as possible to get as much information about your session across.  The summary should be different from the abstract (and don't leave it blank as some people do).  This field is where you can give the reviewers more detail about things like the structure of the talk, possible demonstrations and so on.  As a reviewer I look to this section to help me decide whether the hard-sell of the title and abstract will actually be reflected in the final content.  Try to make this comprehensive, but don't make it excessively long.  When you have to review possibly hundreds of sessions a certain level of conciseness can make life easier for reviewers and help the cause of your session. If you've not made many submissions for talks in the past, or if this is your first, try to give reviewers places to find background on you as a presenter.  Having an active blog and Twitter handle can also help reviewers if they're not sure what your level of expertise is.  Many call-for-papers have places for you to include this type of information.  It's always good to have new and original presenters and presentations for conferences.  Hopefully these tips will help you be successful when you answer the next call-for-papers.

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  • How to change the install path of my Linux Source tree?

    - by Sen
    I was trying to bring up my custom kernel. I did the following : make menuconfig && make modules && make modules_install && make install I would like to change the install PATH. How can i do that? I tried doing export INSTALL_PATH=<my custom path> But then it is only creating the vmlinux.bin(it is not creating the ramdisk image!!) But if i am not doing that, make install will automatically create the ramdisk image in the default /boot folder. How can i change that?? Thanks, Sen

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  • Can I make Puppet's module-to-file mapping to start searching at the top of the modules tree?

    - by John Siracusa
    Consider these two Puppet module files: # File modules/a/manifests/b/c.pp class a::b::c { include b::c } # File modules/b/manifests/c.pp class b::c { notify { "In b::c": } } It seems that when Puppet hits the include b::c directive in class a::b::c, it searches for the corresponding *.pp file by looking backwards from the current class and decides that it find the correct file located at ../../b/c.pp. In other words, it resolves b::c to the same *.pp file that the include b::c statement appears in: modules/a/manifests/b/c.pp I expected it (and would like it) to instead find and load the file modules/b/manifests/c.pp. Is there a way to make Puppet do this? If not, it seems to me that module names may not contain any other module names anywhere within them, which is a pretty surprising restriction.

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  • How can I automatically synchronize a directory tree on multiple machines?

    - by Blacklight Shining
    I have two Mac laptops and a Debian server, each with a directory that I would like to keep in sync between the three. The solution should meet the following criteria (in rough order of importance): It must not use any third-party service (e.g. Dropbox, SugarSync, Google whatever). This does not include installing additional software (as long as it's free). It must not require me to use specific directories or change my way of storing things. (Dropbox does this IIRC) It must work in all directions (changes made on /any/ machine should be pushed to the others) All data sent must be encrypted (I have ssh keypairs set up already) It must work even when not all machines are available (changes should be pushed to a machine when it comes back online) It must work even when the /directories/ on some machines are not available (they may be stored on disk images which will not always be mounted) This can be solved for Macs by using launchd to automatically launch and kill (or in some way change the behavior of) whatever daemon is used for syncing when the images are mounted and unmounted. It must be immediate (using an event-based system, not a periodic one like cron) It must be flexible (if more machines are added, I should be able to incorporate them easily) I also have some preferences that I would like to be fulfilled, but do not have to be: It should notify me somehow if there are conflicts or other errors. It should recognize symbolic and hard links and create corresponding ones. It should allow me to create a list of exceptions (subdirectories which will not be synced at all). It should not require me to set up port forwarding or otherwise reconfigure a network. This can be solved by using an ssh tunnel with reverse port forwarding. If you have a solution that meets some, but not all of the criteria, please contribute it in the comments as it might be useful in some way, and it might be possible to meet some of the criteria separately. What I tried, and why it didn't work: rsync and lsyncd do not support bidirectional synchronization csync2 is designed for server clusters and does not appear to work with machines with dynamic IPs DRBD (suggested by amotzg) involves installing a kernel module and does not appear to work on systems running OS X

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  • Building a Repository Pattern against an EF 5 EDMX Model - Part 1

    - by Juan
    I am part of a year long plus project that is re-writing an existing application for a client.  We have decided to develop the project using Visual Studio 2012 and .NET 4.5.  The project will be using a number of technologies and patterns to include Entity Framework 5, WCF Services, and WPF for the client UI.This is my attempt at documenting some of the successes and failures that I will be coming across in the development of the application.In building the data access layer we have to access a database that has already been designed by a dedicated dba. The dba insists on using Stored Procedures which has made the use of EF a little more difficult.  He will not allow direct table access but we did manage to get him to allow us to use Views.  Since EF 5 does not have good support to do Code First with Stored Procedures, my option was to create a model (EDMX) against the existing database views.   I then had to go select each entity and map the Insert/Update/Delete functions to their respective stored procedure. The next step after I had completed mapping the stored procedures to the entities in the EDMX model was to figure out how to build a generic repository that would work well with Entity Framework 5.  After reading the blog posts below, I adopted much of their code with some changes to allow for the use of Ninject for dependency injection.http://www.tcscblog.com/2012/06/22/entity-framework-generic-repository/ http://www.tugberkugurlu.com/archive/generic-repository-pattern-entity-framework-asp-net-mvc-and-unit-testing-triangle IRepository.cs public interface IRepository : IDisposable where T : class { void Add(T entity); void Update(T entity, int id); T GetById(object key); IQueryable Query(Expression> predicate); IQueryable GetAll(); int SaveChanges(); int SaveChanges(bool validateEntities); } GenericRepository.cs public abstract class GenericRepository : IRepository where T : class { public abstract void Add(T entity); public abstract void Update(T entity, int id); public abstract T GetById(object key); public abstract IQueryable Query(Expression> predicate); public abstract IQueryable GetAll(); public int SaveChanges() { return SaveChanges(true); } public abstract int SaveChanges(bool validateEntities); public abstract void Dispose(); } One of the issues I ran into was trying to do an update. I kept receiving errors so I posted a question on Stack Overflow http://stackoverflow.com/questions/12585664/an-object-with-the-same-key-already-exists-in-the-objectstatemanager-the-object and came up with the following hack. If someone has a better way, please let me know. DbContextRepository.cs public class DbContextRepository : GenericRepository where T : class { protected DbContext Context; protected DbSet DbSet; public DbContextRepository(DbContext context) { if (context == null) throw new ArgumentException("context"); Context = context; DbSet = Context.Set(); } public override void Add(T entity) { if (entity == null) throw new ArgumentException("Cannot add a null entity."); DbSet.Add(entity); } public override void Update(T entity, int id) { if (entity == null) throw new ArgumentException("Cannot update a null entity."); var entry = Context.Entry(entity); if (entry.State == EntityState.Detached) { var attachedEntity = DbSet.Find(id); // Need to have access to key if (attachedEntity != null) { var attachedEntry = Context.Entry(attachedEntity); attachedEntry.CurrentValues.SetValues(entity); } else { entry.State = EntityState.Modified; // This should attach entity } } } public override T GetById(object key) { return DbSet.Find(key); } public override IQueryable Query(Expression> predicate) { return DbSet.Where(predicate); } public override IQueryable GetAll() { return Context.Set(); } public override int SaveChanges(bool validateEntities) { Context.Configuration.ValidateOnSaveEnabled = validateEntities; return Context.SaveChanges(); } #region IDisposable implementation public override void Dispose() { if (Context != null) { Context.Dispose(); GC.SuppressFinalize(this); } } #endregion IDisposable implementation } At this point I am able to start creating individual repositories that are needed and add a Unit of Work.  Stay tuned for the next installment in my path to creating a Repository Pattern against EF5.

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  • Beaglebone Black running Debian, does device tree overlay act as an api?

    - by user3953989
    This maybe more of a Linux specific question but... I've been reading many tutorials and it seems that you can use JavaScript, Python, and C++ to write code for the Beaglebone Black(BBB). It looks like the way C++ interfaces with the BBB hardware is via reading/writing text files on the OS while Python has it's own library. All the C++ examples out there control the GPIO and PWM via reading/writing to text files. Is this the only way to access the hardware or just how Linux does drivers?

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  • 'undefined method init for Mysql:Class'

    - by sscirrus
    I've been having problems with a MySQL Server installation that got messed up after a power outage. Configuration Intel i5 Mac running OS X 10.6.5 Ruby 1.9.2 installed Rails 3.0.1 installed MySQL Server (finally) installed and running I completely reinstalled MySQL, which deleted the local development/test/production databases. So, I have run create database development; in MySQL to get the dev database ready for a migration. Current Goal Run rake db:migrate to get my databases back again. (I cannot currently access my databases or Mysql at all from Rails.) Error Using the gem 'mysql', '2.8.1' and run rake db:migrate, I get the error: rake aborted! undefined method 'init' for Mysql:Class Stack Trace: /Users/sscirrus/.rvm/gems/ruby-1.9.2-p0/gems/activerecord-3.0.1/lib/active_record/connection_adapters/mysql_adapter.rb:30:in 'mysql_connection' /Users/sscirrus/.rvm/gems/ruby-1.9.2-p0/gems/activerecord-3.0.1/lib/active_record/connection_adapters/abstract/connection_pool.rb:230:in 'new_connection' /Users/sscirrus/.rvm/gems/ruby-1.9.2-p0/gems/activerecord-3.0.1/lib/active_record/connection_adapters/abstract/connection_pool.rb:238:in 'checkout_new_connection' /Users/sscirrus/.rvm/gems/ruby-1.9.2-p0/gems/activerecord-3.0.1/lib/active_record/connection_adapters/abstract/connection_pool.rb:194:in 'block (2 levels) in checkout' /Users/sscirrus/.rvm/gems/ruby-1.9.2-p0/gems/activerecord-3.0.1/lib/active_record/connection_adapters/abstract/connection_pool.rb:190:in 'loop' /Users/sscirrus/.rvm/gems/ruby-1.9.2-p0/gems/activerecord-3.0.1/lib/active_record/connection_adapters/abstract/connection_pool.rb:190:in 'block in checkout' /Users/sscirrus/.rvm/rubies/ruby-1.9.2-p0/lib/ruby/1.9.1/monitor.rb:201:in 'mon_synchronize' /Users/sscirrus/.rvm/gems/ruby-1.9.2-p0/gems/activerecord-3.0.1/lib/active_record/connection_adapters/abstract/connection_pool.rb:189:in 'checkout' /Users/sscirrus/.rvm/gems/ruby-1.9.2-p0/gems/activerecord-3.0.1/lib/active_record/connection_adapters/abstract/connection_pool.rb:96:in 'connection' /Users/sscirrus/.rvm/gems/ruby-1.9.2-p0/gems/activerecord-3.0.1/lib/active_record/connection_adapters/abstract/connection_pool.rb:318:in 'retrieve_connection' /Users/sscirrus/.rvm/gems/ruby-1.9.2-p0/gems/activerecord-3.0.1/lib/active_record/connection_adapters/abstract/connection_specification.rb:97:in 'retrieve_connection' /Users/sscirrus/.rvm/gems/ruby-1.9.2-p0/gems/activerecord-3.0.1/lib/active_record/connection_adapters/abstract/connection_specification.rb:89:in 'connection' /Users/sscirrus/.rvm/gems/ruby-1.9.2-p0/gems/activerecord-3.0.1/lib/active_record/migration.rb:486:in 'initialize' /Users/sscirrus/.rvm/gems/ruby-1.9.2-p0/gems/activerecord-3.0.1/lib/active_record/migration.rb:433:in 'new' /Users/sscirrus/.rvm/gems/ruby-1.9.2-p0/gems/activerecord-3.0.1/lib/active_record/migration.rb:433:in 'up' /Users/sscirrus/.rvm/gems/ruby-1.9.2-p0/gems/activerecord-3.0.1/lib/active_record/migration.rb:415:in 'migrate' /Users/sscirrus/.rvm/gems/ruby-1.9.2-p0/gems/activerecord-3.0.1/lib/active_record/railties/databases.rake:142:in 'block (2 levels) in <top (required)>' /Users/sscirrus/.rvm/gems/ruby-1.9.2-p0/gems/rake-0.8.7/lib/rake.rb:636:in 'call' /Users/sscirrus/.rvm/gems/ruby-1.9.2-p0/gems/rake-0.8.7/lib/rake.rb:636:in 'block in execute' /Users/sscirrus/.rvm/gems/ruby-1.9.2-p0/gems/rake-0.8.7/lib/rake.rb:631:in 'each' /Users/sscirrus/.rvm/gems/ruby-1.9.2-p0/gems/rake-0.8.7/lib/rake.rb:631:in 'execute' /Users/sscirrus/.rvm/gems/ruby-1.9.2-p0/gems/rake-0.8.7/lib/rake.rb:597:in 'block in invoke_with_call_chain' /Users/sscirrus/.rvm/rubies/ruby-1.9.2-p0/lib/ruby/1.9.1/monitor.rb:201:in 'mon_synchronize' /Users/sscirrus/.rvm/gems/ruby-1.9.2-p0/gems/rake-0.8.7/lib/rake.rb:590:in 'invoke_with_call_chain' /Users/sscirrus/.rvm/gems/ruby-1.9.2-p0/gems/rake-0.8.7/lib/rake.rb:583:in 'invoke' /Users/sscirrus/.rvm/gems/ruby-1.9.2-p0/gems/rake-0.8.7/lib/rake.rb:2051:in 'invoke_task' /Users/sscirrus/.rvm/gems/ruby-1.9.2-p0/gems/rake-0.8.7/lib/rake.rb:2029:in 'block (2 levels) in top_level' /Users/sscirrus/.rvm/gems/ruby-1.9.2-p0/gems/rake-0.8.7/lib/rake.rb:2029:in 'each' /Users/sscirrus/.rvm/gems/ruby-1.9.2-p0/gems/rake-0.8.7/lib/rake.rb:2029:in 'block in top_level' /Users/sscirrus/.rvm/gems/ruby-1.9.2-p0/gems/rake-0.8.7/lib/rake.rb:2068:in 'standard_exception_handling' /Users/sscirrus/.rvm/gems/ruby-1.9.2-p0/gems/rake-0.8.7/lib/rake.rb:2023:in 'top_level' /Users/sscirrus/.rvm/gems/ruby-1.9.2-p0/gems/rake-0.8.7/lib/rake.rb:2001:in 'block in run' /Users/sscirrus/.rvm/gems/ruby-1.9.2-p0/gems/rake-0.8.7/lib/rake.rb:2068:in 'standard_exception_handling' /Users/sscirrus/.rvm/gems/ruby-1.9.2-p0/gems/rake-0.8.7/lib/rake.rb:1998:in 'run' /Users/sscirrus/.rvm/gems/ruby-1.9.2-p0/gems/rake-0.8.7/bin/rake:31:in '<top (required)>' /Users/sscirrus/.rvm/gems/ruby-1.9.2-p0/bin/rake:19:in 'load' /Users/sscirrus/.rvm/gems/ruby-1.9.2-p0/bin/rake:19:in '<main>'

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  • What is the proper query to get all the children in a tree?

    - by Nathan Adams
    Lets say I have the following MySQL structure: CREATE TABLE `domains` ( `id` INT(10) UNSIGNED NOT NULL AUTO_INCREMENT, `domain` CHAR(50) NOT NULL, `parent` INT(11) DEFAULT NULL, PRIMARY KEY (`id`) ) ENGINE=MYISAM AUTO_INCREMENT=10 DEFAULT CHARSET=latin1 insert into `domains`(`id`,`domain`,`parent`) values (1,'.com',0); insert into `domains`(`id`,`domain`,`parent`) values (2,'example.com',1); insert into `domains`(`id`,`domain`,`parent`) values (3,'sub1.example.com',2); insert into `domains`(`id`,`domain`,`parent`) values (4,'sub2.example.com',2); insert into `domains`(`id`,`domain`,`parent`) values (5,'s1.sub1.example.com',3); insert into `domains`(`id`,`domain`,`parent`) values (6,'s2.sub1.example.com',3); insert into `domains`(`id`,`domain`,`parent`) values (7,'sx1.s1.sub1.example.com',5); insert into `domains`(`id`,`domain`,`parent`) values (8,'sx2.s2.sub1.example.com',6); insert into `domains`(`id`,`domain`,`parent`) values (9,'x.sub2.example.com',4); In my mind that is enough to emulate a simple tree structure: .com | example / \ sub1 sub2 ect My problem is that give sub1.example.com I want to know all the children of sub1.example.com without using multiple queries in my code. I have tried joining the table to itself and tried to use subqueries, I can't think of anything that will reveal all the children. At work we are using MPTT to keep in hierarchal order a list of domains/subdomains however, I feel that there is an easier way to do it. I did some digging and someone did something similar but they required the use of a function in MySQL. I don't think for something simple like this we would need a whole function. Maybe I am just dumb and not seeing some sort of obvious solution. Also, feel free to alter the structure.

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  • Is there any way to access files in your source tree in Android?

    - by Chris Thompson
    Hi all, This is a bit unorthodox but I'm trying to figure out if there's a way to access files stored in the src tree of my applications apk in Android. I'm trying to use i-Jetty (Jetty implementation for Android) and rather than use it as a separate application and manually download my war file, I'd rather just bake i-jetty in. However, in order to use (easily) standard html/jsp I need to be able to give it a document root, preferably within my application's apk file. I know Android specifically works to prevent you from accessing (freely) the stuff on the actual system so this may not be possible, but I'm thinking it might be possible to access something within the apk. One option to work around this would be to have all of the files stored in the res directory and then copy them to the sdcard on startup but this wouldn't allow me to automatically remove the files on uninstall. To give you an idea of what I've tried, currently, the html files are stored in org.webtext.android Context rootContext = new Context(server_, "/", Context.SESSIONS); rootContext.setResourceBase("org/webtext/webapp"); Returns a 404 error. final URL url = this.getClassLoader().getResource("org/webtext/webapp"); Context html = new WebAppContext(url.toExternalForm(), "/"); Blows up with a NullPointerException because no URL is returned from the getResource call. Any thoughts would be greatly appreciated! Thanks, Chris

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  • Is a red-black tree my ideal data structure?

    - by Hugo van der Sanden
    I have a collection of items (big rationals) that I'll be processing. In each case, processing will consist of removing the smallest item in the collection, doing some work, and then adding 0-2 new items (which will always be larger than the removed item). The collection will be initialised with one item, and work will continue until it is empty. I'm not sure what size the collection is likely to reach, but I'd expect in the range 1M-100M items. I will not need to locate any item other than the smallest. I'm currently planning to use a red-black tree, possibly tweaked to keep a pointer to the smallest item. However I've never used one before, and I'm unsure whether my pattern of use fits its characteristics well. 1) Is there a danger the pattern of deletion from the left + random insertion will affect performance, eg by requiring a significantly higher number of rotations than random deletion would? Or will delete and insert operations still be O(log n) with this pattern of use? 2) Would some other data structure give me better performance, either because of the deletion pattern or taking advantage of the fact I only ever need to find the smallest item? Update: glad I asked, the binary heap is clearly a better solution for this case, and as promised turned out to be very easy to implement. Hugo

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  • Implementation question involving implementing an interface

    - by Vivin Paliath
    I'm writing a set of collection classes for different types of Trees. I'm doing this as a learning exercise and I'm also hoping it turns out to be something useful. I really want to do this the right way and so I've been reading Effective Java and I've also been looking at the way Joshua Bloch implemented the collection classes by looking at the source. I seem to have a fair idea of what is being done, but I still have a few things to sort out. I have a Node<T> interface and an AbstractNode<T> class that implements the Node interface. I then created a GenericNode<T> (a node that can have 0 to n children, and that is part of an n-ary tree) class that extends AbstractNode<T> and implements Node<T>. This part was easy. Next, I created a Tree<T> interface and an AbstractTree<T> class that implements the Tree<T> interface. After that, I started writing a GenericTree<T> class that extends AbstractTree<T> and implements Tree<T>. This is where I started having problems. As far as the design is concerned, a GenericTree<T> can only consist of nodes of type GenericTreeNode<T>. This includes the root. In my Tree<T> interface I have: public interface Tree<T> { void setRoot(Node<T> root); Node<T> getRoot(); List<Node<T>> postOrder(); ... rest omitted ... } And, AbstractTree<T> implements this interface: public abstract class AbstractTree<T> implements Tree<T> { protected Node<T> root; protected AbstractTree() { } protected AbstractTree(Node<T> root) { this.root = root; } public void setRoot(Node<T> root) { this.root = root; } public Node<T> getRoot() { return this.root; } ... rest omitted ... } In GenericTree<T>, I can have: public GenericTree(Node<T> root) { super(root); } But what this means is that you can create a generic tree using any subtype of Node<T>. You can also set the root of a tree to any subtype of Node<T>. I want to be able to restrict the type of the node to the type of the tree that it can represent. To fix this, I can do this: public GenericTree(GenericNode<T> root) { super(root); } However, setRoot still accepts a parameter of type Node<T>. Which means a user can still create a tree with the wrong type of root node. How do I enforce this constraint? The only way I can think of doing is either: Do an instanceof which limits the check to runtime. I'm not a huge fan of this. Remove setRoot from the interface and have the base class implement this method. This means that it is not part of the contract and anyone who wants to make a new type of tree needs to remember to implement this method. Is there a better way? The second question I have concerns the return type of postOrder which is List<Node<T>>. This means that if a user is operating on a GenericTree<T> object and calls postOrder, he or she receives a list that consists of Node<T> objects. This means when iterating through (using a foreach construct) they would have perform an explicit cast to GenericNode<T> if they want to use methods that are only defined in that class. I don't like having to place this burden on the user. What are my options in this case? I can only think of removing the method from the interface and have the subclass implement this method making sure that it returns a list of appropriate subtype of Node<T>. However, this once again removes it from the contract and it's anyone who wants to create a new type of tree has to remember to implement this method. Is there a better way?

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  • Why boost property tree write_json saves everything as string? Is it possible to change that?

    - by pprzemek
    I'm trying to serialize using boost property tree write_json, it saves everything as strings, it's not that data are wrong, but I need to cast them explicitly every time and I want to use them somewhere else. (like in python or other C++ json (non boost) library) here is some sample code and what I get depending on locale: boost::property_tree::ptree root, arr, elem1, elem2; elem1.put<int>("key0", 0); elem1.put<bool>("key1", true); elem2.put<float>("key2", 2.2f); elem2.put<double>("key3", 3.3); arr.push_back( std::make_pair("", elem1) ); arr.push_back( std::make_pair("", elem2) ); root.put_child("path1.path2", arr); std::stringstream ss; write_json(ss, root); std::string my_string_to_send_somewhare_else = ss.str(); and my_string_to_send_somewhere_else is sth. like this: { "path1" : { "path2" : [ { "key0" : "0", "key1" : "true" }, { "key2" : "2.2", "key3" : "3.3" } ] } } Is there anyway to save them as the values, like: "key1" : true or "key2" : 2.2 ?

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  • How can I SETF an element in a tree by an accessor?

    - by Willi Ballenthin
    We've been using Lisp in my AI course. The assignments I've received have involved searching and generating tree-like structures. For each assignment, I've ended up writing something like: (defun initial-state () (list 0 ; score nil ; children 0 ; value 0)) ; something else and building my functions around these "states", which are really just nested lists with some loosely defined structure. To make the structure more rigid, I've tried to write accessors, such as: (defun state-score ( state ) (nth 2 state)) This works for reading the value (which should be all I need to do in a nicely functional world. However, as time crunches, and I start to madly hack, sometimes I want a mutable structure). I don't seem to be able to SETF the returned ...thing (place? value? pointer?). I get an error with something like: (setf (state-score *state*) 10) Sometimes I seem to have a little more luck writing the accessor/mutator as a macro: (defmacro state-score ( state ) `(nth 2 ,state)) However I don't know why this should be a macro, so I certainly shouldn't write it as a macro (except that sometimes it works. Programming by coincidence is bad). What is an appropriate strategy to build up such structures? More importantly, where can I learn about whats going on here (what operations affect the memory in what way)?

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  • How do implement a breadth first traversal?

    - by not looking for answer
    //This is what I have. I thought pre-order was the same and mixed it up with depth first! import java.util.LinkedList; import java.util.Queue; public class Exercise25_1 { public static void main(String[] args) { BinaryTree tree = new BinaryTree(new Integer[] {10, 5, 15, 12, 4, 8 }); System.out.print("\nInorder: "); tree.inorder(); System.out.print("\nPreorder: "); tree.preorder(); System.out.print("\nPostorder: "); tree.postorder(); //call the breadth method to test it System.out.print("\nBreadthFirst:"); tree.breadth(); } } class BinaryTree { private TreeNode root; /** Create a default binary tree */ public BinaryTree() { } /** Create a binary tree from an array of objects */ public BinaryTree(Object[] objects) { for (int i = 0; i < objects.length; i++) { insert(objects[i]); } } /** Search element o in this binary tree */ public boolean search(Object o) { return search(o, root); } public boolean search(Object o, TreeNode root) { if (root == null) { return false; } if (root.element.equals(o)) { return true; } else { return search(o, root.left) || search(o, root.right); } } /** Return the number of nodes in this binary tree */ public int size() { return size(root); } public int size(TreeNode root) { if (root == null) { return 0; } else { return 1 + size(root.left) + size(root.right); } } /** Return the depth of this binary tree. Depth is the * number of the nodes in the longest path of the tree */ public int depth() { return depth(root); } public int depth(TreeNode root) { if (root == null) { return 0; } else { return 1 + Math.max(depth(root.left), depth(root.right)); } } /** Insert element o into the binary tree * Return true if the element is inserted successfully */ public boolean insert(Object o) { if (root == null) { root = new TreeNode(o); // Create a new root } else { // Locate the parent node TreeNode parent = null; TreeNode current = root; while (current != null) { if (((Comparable)o).compareTo(current.element) < 0) { parent = current; current = current.left; } else if (((Comparable)o).compareTo(current.element) > 0) { parent = current; current = current.right; } else { return false; // Duplicate node not inserted } } // Create the new node and attach it to the parent node if (((Comparable)o).compareTo(parent.element) < 0) { parent.left = new TreeNode(o); } else { parent.right = new TreeNode(o); } } return true; // Element inserted } public void breadth() { breadth(root); } // Implement this method to produce a breadth first // search traversal public void breadth(TreeNode root){ if (root == null) return; System.out.print(root.element + " "); breadth(root.left); breadth(root.right); } /** Inorder traversal */ public void inorder() { inorder(root); } /** Inorder traversal from a subtree */ private void inorder(TreeNode root) { if (root == null) { return; } inorder(root.left); System.out.print(root.element + " "); inorder(root.right); } /** Postorder traversal */ public void postorder() { postorder(root); } /** Postorder traversal from a subtree */ private void postorder(TreeNode root) { if (root == null) { return; } postorder(root.left); postorder(root.right); System.out.print(root.element + " "); } /** Preorder traversal */ public void preorder() { preorder(root); } /** Preorder traversal from a subtree */ private void preorder(TreeNode root) { if (root == null) { return; } System.out.print(root.element + " "); preorder(root.left); preorder(root.right); } /** Inner class tree node */ private class TreeNode { Object element; TreeNode left; TreeNode right; public TreeNode(Object o) { element = o; } } }

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  • Which templating languages output HTML *as a tree of nodes*?

    - by alamar
    HTML is a tree of nodes, before all. It's not just a text. However, most templating engines handle their input and output as it was just a text; they don't care what happens around their tags, their {$foo}'s and <% bar() %>'s; also they don't care about what are they outputting. Sometimes they happen to produce a correct html, but that's just a coincidence; they didn't aim for that, all they wanted is to replace some funny marks in the text stream with their evaluation. There are a few templating engines which do treat their output as a set of nodes; XSLT and Haml come to mind. For some tasks, this has advantages: for example, you can automatically reformat (like, delete all empty text nodes; auto-indent; word-wrap). The result is guaranteed to be a correct xml/sgml unless you use a strict subset of operations that can break that. Also, such templating engine would automatically quote strings, differently in text nodes and in attributes, because it strictly knows whether you're writing an attribute or a text node. Moreover, it can conditionally remove a node from output because it knows where it does begin and end, which is useful, and do other non-trivial node operations. You might not like XSLT for its verbosiness or functionalness, but it's damn helps that your template is xmllint-able XML, and your output is a good sgml/xml. So the question is: Which template engines do you know that treat their output as a set of correct nodes, not just an unstructured text? I know XSLT, Haml and some obscure python-based one. Moar!

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  • How do I add an object to a binary tree based on the value of a member variable?

    - by Max
    How can I get a specific value from an object? I'm trying to get a value of an instance for eg. ListOfPpl newListOfPpl = new ListOfPpl(id, name, age); Object item = newListOfPpl; How can I get a value of name from an Object item?? Even if it is easy or does not interest you can anyone help me?? Edited: I was trying to build a binary tree contains the node of ListOfPpl, and need to sort it in the lexicographic. Here's my code for insertion on the node. Any clue?? public void insert(Object item){ Node current = root; Node follow = null; if(!isEmpty()){ root = new Node(item, null, null); return; }boolean left = false, right = false; while(current != null){ follow = current; left = false; right = false; //I need to compare and sort it if(item.compareTo(current.getFighter()) < 0){ current = current.getLeft(); left = true; }else { current = current.getRight(); right = true; } }if(left) follow.setLeft(new Node(item, null, null)); else follow.setRight(new Node(item, null, null)); }

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  • EF code first error "The specified index already exists. [ IX_Id ]" for object tree

    - by PascalN
    Using EF code first 4.3 I'm trying to model an object tree with a required-required relationships and a required-optional relationships. Here is a simple representation of those classes public class Top { public int Id { get; set; } public virtual Middle Middle { get; set; } } public class Middle { public int Id { get; set; } public virtual Child Child { get; set; } } public class Child { public int Id { get; set; } } Here is the OnModelCreating code modelBuilder.Entity<Top>().HasRequired(t => t.Middle).WithRequiredPrincipal().WillCascadeOnDelete(); modelBuilder.Entity<Middle>().HasRequired(t => t.Child).WithOptional().WillCascadeOnDelete(); This produces the error "The specified index already exists. [ IX_Id ]" on SQLCE After checking the db schema, both model binder fluent API configuration lines create an index IX_Id on the table Middles. Does anyone know how to work around that problem? Is there a way to set the index name? Thank you! Pascal

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  • How do I code a tree of objects in Haskell with pointers to parent and children?

    - by axilmar
    I've got the following problem: I have a tree of objects of different classes where an action in the child class invalidates the parent. In imperative languages, it is trivial to do. For example, in Java: public class A { private List<B> m_children = new LinkedList<B>(); private boolean m_valid = true; public void invalidate() { m_valid = false; } public void addChild(B child) { m_children.add(child); child.m_parent = this; } } public class B { public A m_parent = null; private int m_data = 0; public void setData(int data) { m_data = 0; m_parent.invalidate(); } } public class Main { public static void main(String[] args) { A a = new A(); B b = new B(); b.setData(0); //invalidates A } } How do I do the above in Haskell? I cannot wrap my mind around this, since once I construct an object in Haskell, it cannot be changed. I would be much obliged if the relevant Haskell code is posted.

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  • Is this Leftist Tree piece of code from Wikipedia correct?

    - by they changed my name
    Link public Node merge(Node x, Node y) { if(x == null) return y; if(y == null) return x; // if this was a max height biased leftist tree, then the // next line would be: if(x.element < y.element) if(x.element.compareTo(y.element) > 0) { // x.element > y.element Node temp = x; x = y; y = temp; } x.rightChild = merge(x.rightChild, y); if(x.leftChild == null) { // left child doesn't exist, so move right child to the left side x.leftChild = x.rightChild; x.rightChild = null; x.s = 1; } else { // left child does exist, so compare s-values if(x.leftChild.s < x.rightChild.s) { Node temp = x.leftChild; x.leftChild = x.rightChild; x.rightChild = temp; } // since we know the right child has the lower s-value, we can just // add one to its s-value x.s = x.rightChild.s + 1; } return x; } What makes me ask this question is: if(x.element.compareTo(y.element) > 0) { // x.element > y.element Node temp = x; x = y; y = temp; } Isn't that just not gonna work, since the references are only switched inside the method?

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  • "Error: Phone reports generic communication error or syntax error. (GsmComm.GsmCommunication.CommEx

    - by kiran
    hey guys, i was checking the sample code with gsmComm library, my modem is nokia 5130 Xpressmusic modem and the connection was done successfuly but when i tried to send a SMS .. i got this message "Error: Phone reports generic communication error or syntax error. (GsmComm.GsmCommunication.CommException)" what's the problem ?http://www.codeproject.com/KB/cs/SMS.aspx is ther any other codes ...

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