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  • strange redefined symbols

    - by Chris H
    I included this header into one of my own: http://codepad.org/lgJ6KM6b When I compiled I started getting errors like this: CMakeFiles/bin.dir/SoundProjection.cc.o: In function `Gnuplot::reset_plot()': /usr/lib/gcc/x86_64-pc-linux-gnu/4.3.4/include/g++-v4/new:105: multiple definition of `Gnuplot::reset_plot()' CMakeFiles/bin.dir/main.cc.o:project/gnuplot-cpp/gnuplot_i.hpp:962: first defined here CMakeFiles/bin.dir/SoundProjection.cc.o: In function `Gnuplot::set_smooth(std::basic_string, std::allocator const&)': project/gnuplot-cpp/gnuplot_i.hpp:1041: multiple definition of `Gnuplot::set_smooth(std::basic_string, std::allocator const&)' CMakeFiles/bin.dir/main.cc.o:project/gnuplot-cpp/gnuplot_i.hpp:1041: first defined here CMakeFiles/bin.dir/SoundProjection.cc.o:/usr/include/eigen2/Eigen/src/Core/arch/SSE/PacketMath.h:41: multiple definition of `Gnuplot::m_sGNUPlotFileName' I know it's hard to see in this mess, but look at where the redefinitions are taking place. They take place in files like /usr/lib/gcc/x86_64-pc-linux-gnu/4.3.4/include/g++-v4/new:105. How is the new operator getting information about a gnuplot header? I can't even edit that file. How could that ever even be possible? I'm not even sure how to start debugging this. I hope I've provided enough information. I wasn't able to reproduce this in a small project. I mostly just looking for tips on how to find out why this is happening, and how to track it down. Thanks.

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  • Polymorphic Numerics on .Net and In C#

    - by Bent Rasmussen
    It's a real shame that in .Net there is no polymorphism for numbers, i.e. no INumeric interface that unifies the different kinds of numerical types such as bool, byte, uint, int, etc. In the extreme one would like a complete package of abstract algebra types. Joe Duffy has an article about the issue: http://www.bluebytesoftware.com/blog/CommentView,guid,14b37ade-3110-4596-9d6e-bacdcd75baa8.aspx How would you express this in C#, in order to retrofit it, without having influence over .Net or C#? I have one idea that involves first defining one or more abstract types (interfaces such as INumeric - or more abstract than that) and then defining structs that implement these and wrap types such as int while providing operations that return the new type (e.g. Integer32 : INumeric; where addition would be defined as public Integer32 Add(Integer32 other) { return Return(Value + other.Value); } I am somewhat afraid of the execution speed of this code but at least it is abstract. No operator overloading goodness... Any other ideas? .Net doesn't look like a viable long-term platform if it cannot have this kind of abstraction I think - and be efficient about it. Abstraction is reuse.

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  • Triangle numbers problem....show within 4 seconds

    - by Daredevil
    The sequence of triangle numbers is generated by adding the natural numbers. So the 7th triangle number would be 1 + 2 + 3 + 4 + 5 + 6 + 7 = 28. The first ten terms would be: 1, 3, 6, 10, 15, 21, 28, 36, 45, 55, ... Let us list the factors of the first seven triangle numbers: 1: 1 3: 1,3 6: 1,2,3,6 10: 1,2,5,10 15: 1,3,5,15 21: 1,3,7,21 28: 1,2,4,7,14,28 We can see that 28 is the first triangle number to have over five divisors. Given an integer n, display the first triangle number having at least n divisors. Sample Input: 5 Output 28 Input Constraints: 1<=n<=320 I was obviously able to do this question, but I used a naive algorithm: Get n. Find triangle numbers and check their number of factors using the mod operator. But the challenge was to show the output within 4 seconds of input. On high inputs like 190 and above it took almost 15-16 seconds. Then I tried to put the triangle numbers and their number of factors in a 2d array first and then get the input from the user and search the array. But somehow I couldn't do it: I got a lot of processor faults. Please try doing it with this method and paste the code. Or if there are any better ways, please tell me.

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  • Dynamically created operators

    - by Gero
    I created a program using dev-cpp and wxwidgets which solves a puzzle. The user must fill the operations blocks and the results blocks, and the program will solve it. Im solving it using bruteforce, i generate all non repeated 9 length number combinations using a recursive algorithm. It does it pretty fast. Up to here all is great! But the problem is when my program operates depending the character on the blocks. Its extremely slow (it never gets the answer), because of the chars comparation against +, -, *, etc. Im doing a CASE. Is there some way or some programming language wich allows dinamic creation of operators? So i can define the operator ROW1COL2 to be a +, and the same way to all other operations. I leave a screenshot of the app, so its easier to understand how the puzzle works. http://www.imageshare.web.id/images/9gg5cev8vyokp8rhlot9.png PD: The algorithm works, i tryed it with a trivial puzzle, and solved it in a second.

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  • Spring 2.5 managed servlets: howto?

    - by EugeneP
    Correct me if anything is wrong. As I understand, all Spring functionality, namely DI works when beans are got thru Spring Context, ie getBean() method. Otherwise, none can work, even if my method is marked @Transactional and I will create the owning class with a new operator, no transaction management will be provided. I use Tomcat 6 as a servlet container. So, my question is: how to make Servlet methods managed by Spring framework. The issue here is that I use a framework, and its servlets extend the functionality of basic java Servlets, so they have more methods. Still, web.xml is present in an app as usual. The thing is that I do not control the servlets creation flow, I can only override a few methods of each servlet, the flow is basically written down in some xml file, but I control this process using a graphical gui. So, basically, I only add some code to a few methods of each Servlet. How to make those methods managed by Spring framework? The basic thing I need to do is making these methods transactional (@Transactional).

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  • Building an *efficient* if/then interface for non-technical users to build flow-control in PHP

    - by Brendan
    I am currently building an internal tool to be used by our management to control the flow of traffic. I have built an if/then interface allowing the user to set conditions for certain outcomes, however it is inefficient to use the switch statement to control the flow. How can I improve the efficiency of my code? Example of code: if($previous['route_id'] == $condition['route_id'] && $failed == 0) //if we have not moved on to a new set of rules and we haven't failed yet { switch($condition['type']) { case 0 : $type = $user['hour']; break; case 1 : $type = $user['location']['region_abv']; break; case 2 : $type = $user['referrer_domain']; break; case 3 : $type = $user['affiliate']; break; case 4 : $type = $user['location']['country_code']; break; case 5 : $type = $user['location']['city']; break; } $type = strtolower($type); $condition['value'] = strtolower($condition['value']); switch($condition['operator']) { case 0 : if($type == $condition['value']); else $failed = '1'; break; case 1 : if($type != $condition['value']); else $failed = '1'; break; case 2 : if($type > $condition['value']); else $failed = '1'; break; case 3 : if($type >= $condition['value']); else $failed = '1'; break; case 4 : if($type < $condition['value']); else $failed = '1'; break; case 5 : if($type <= $condition['value']); else $failed = '1'; break; } }

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  • Boost class/struct serialization to byte array

    - by Dave18
    does boost library provide functions to pack the class/struct data into a byte array to shorten the length of serialized data? Currently i'm using stringstream to get the serialized data, for example - struct data { std::string s1; std::string s2; int i; }; template <typename Archive> void serialize(Archive &ar, data &d, const unsigned int version) { ar & d.s1; ar & d.s2; ar & d.i; } int main() { data d; d.s1 = "This is my first string"; d.s2 = "This is my second string"; d.i = 10000; std::stringstream archive_stream; boost::archive::text_oarchive archive(archive_stream); archive.operator <<(d); } How would i use a byte array instead of stringstream for data?

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  • Why is Collection<String>.class Illegal?

    - by Peter
    I am puzzled by generics. You can declare a field like: Class<Collection<String>> clazz = ... It seems logical that you could assign this field with: Class<Collection<String>> clazz = Collection<String>.class; However, this generates an error: Syntax error on token ">", void expected after this token So it looks like the .class operator does not work with generics. So I tried: class A<S> {} class B extends A<String> {} Class<A<String>> c = B.class; Also does not work, generates: Type mismatch: cannot convert from Class<Test.StringCollection> to Class<Collection<String>> Now, I really fail to see why this should not work. I know generic types are not reified but in both cases it seems to be fully type safe without having access to runtime generic types. Anybody an idea? Peter Kriens

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  • Linking error while using Qt static built libraries

    - by Kamran Amini
    I hope this is not a duplicate. Recently I'm developing a native C++ application using Qt 4.8.3 and VS2008. Since clients run the application on their naked machines, they need to install VC++ 2008 Redistribution package. So I decided to make it statically linked. I changed my project settings (C/C++ Code Generation Runtime Library) to /MTd. Also I compiled Qt again, this time using following commands for a static building; originally found on this blog Static Qt with static CRT (VS 2008) 1- replaced -MD with -MT in lines QMAKE_CFLAGS_RELEASE and QMAKE_CFLAGS_DEBUG in %QDIR%\mkspecs\win32-msvc2008\qmake.conf 2- nmake confclean 3- configure -static -platform win32-msvc2008 -no-webkit 4- nmake sub-src I compiled Qt successfully. But when I tried again to compile my application, it gave me some strange errors. 1>Linking... 1>qtmaind.lib(qtmain_win.obj) : error LNK2005: "public: bool __thiscall QBasicAtomicInt::deref(void)" (?deref@QBasicAtomicInt@@QAE_NXZ) already defined in QtCored4.lib(QtCored4.dll) 1>qtmaind.lib(qtmain_win.obj) : error LNK2005: "public: bool __thiscall QBasicAtomicInt::operator!=(int)const " (??9QBasicAtomicInt@@QBE_NH@Z) already defined in QtCored4.lib(QtCored4.dll) 1>qtmaind.lib(qtmain_win.obj) : error LNK2005: "public: __thiscall QString::~QString(void)" (??1QString@@QAE@XZ) already defined in QtCored4.lib(QtCored4.dll) I changed some lib files but with each change, situation got worse; for example I tried to use QtCored.lib instead of QtCored4.lib because it is newly created after compilation. I think I've missed something in building static Qt libs. Thanks.

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  • Nicely representing a floating-point number in python

    - by dln385
    I want to represent a floating-point number as a string rounded to some number of significant digits, and never using the exponential format. Essentially, I want to display any floating-point number and make sure it “looks nice”. There are several parts to this problem: I need to be able to specify the number of significant digits. The number of significant digits needs to be variable, which can't be done with with the string formatting operator. I need it to be rounded the way a person would expect, not something like 1.999999999999 I've figured out one way of doing this, though it looks like a work-round and it's not quite perfect. (The maximum precision is 15 significant digits.) >>> def f(number, sigfig): return ("%.15f" % (round(number, int(-1 * floor(log10(number)) + (sigfig - 1))))).rstrip("0").rstrip(".") >>> print f(0.1, 1) 0.1 >>> print f(0.0000000000368568, 2) 0.000000000037 >>> print f(756867, 3) 757000 Is there a better way to do this? Why doesn't Python have a built-in function for this?

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  • Can I use a property placeholder with Spring EL?

    - by David Easley
    Before upgrading to Spring 3 I had this in my applicationContext.xml file: <bean class="com.northgateis.pole.ws.PolePayloadValidatingInterceptor"> <property name="validateRequest" value="${validateRequest}" /> <property name="validateResponse" value="${validateResponse}" /> </bean> where ${validateRequest) and ${validateRequest) refer to properties that may or may not be defined in my properties file. In Spring 2, if these proeprties were not present in the properties file the setters on the bean were not called and so the defaults hard-coded in PolePayloadValidatingInterceptor were used. After upgrading to Spring 3, it seems the behaviour is different: If the properties are not present in the properties file I get the following exception: SEVERE: Exception sending context initialized event to listener instance of class org.springframework.web.context.ContextLoaderListener org.springframework.beans.factory.BeanDefinitionStoreException: Invalid bean definition with name 'annotationMapping' defined in class path resource [com/northgateis/pole/ws/applicationContext-ws.xml]: Could not resolve placeholder 'validateRequest' at org.springframework.beans.factory.config.PropertyPlaceholderConfigurer.processProperties(PropertyPlaceholderConfigurer.java:272) at org.springframework.beans.factory.config.PropertyResourceConfigurer.postProcessBeanFactory(PropertyResourceConfigurer.java:75) at org.springframework.context.support.AbstractApplicationContext.invokeBeanFactoryPostProcessors(AbstractApplicationContext.java:640) at org.springframework.context.support.AbstractApplicationContext.invokeBeanFactoryPostProcessors(AbstractApplicationContext.java:615) at org.springframework.context.support.AbstractApplicationContext.refresh(AbstractApplicationContext.java:405) at org.springframework.web.context.ContextLoader.createWebApplicationContext(ContextLoader.java:272) I tried dabbling with Spring EL but the following doesn't seem to work: <bean class="com.northgateis.pole.ws.PolePayloadValidatingInterceptor"> <property name="validateRequest" value="${validateRequest?:true}" /> <property name="validateResponse" value="${validateResponse?:false}" /> </bean> The value after the Elvis operator is always used, even when the properties are defined in the proeprties file. Interesting that the syntax is accepted. Any suggestions?

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  • C++ stack for multiple data types (RPN vector calculator)

    - by Arrieta
    Hello: I have designed a quick and basic vector arithmetic library in C++. I call the program from the command line when I need a rapid cross product, or angle between vectors. I don't use Matlab or Octave or related, because the startup time is larger than the computation time. Again, this is for very basic operations. I am extending this program, and I will make it work as an RPN calculator, for operations of the type: 1 2 3 4 5 6 x out: -3 6 -3 (give one vector, another vector, and the "cross" operator; spit out the cross product) The stack must accept 3d vectors or scalars, for operations like: 1 2 3 2 * out: 2 4 6 The lexer and parser for this mini-calculator are trivial, but I cannot seem to think of a good way for creating the internal stack. How would you create a stack of for containing vectors or doubles (I rolled up my own very simple vector class - less than one hundred lines and it does everything I need). How can I create a simple stack which accepts elements of class Vector or type double? Thank you.

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  • Cache Class compilation error using parent-child relationships and cache sql storage

    - by Fred Altman
    I have the global listed below that I'm trying to create a couple of cache classes using sql stoarage for: ^WHEAIPP(1,26,1)=2 ^WHEAIPP(1,26,1,1)="58074^^SMSNARE^58311" 2)="58074^59128^MPHILLIPS^59135" ^WHEAIPP(1,29,1)=2 ^WHEAIPP(1,29,1,1)="58074^^SMSNARE^58311" 2)="58074^59128^MPHILLIPS^59135" ^WHEAIPP(1,93,1)=2 ^WHEAIPP(1,93,1,1)="58884^^SSNARE^58948" 2)="58884^59128^MPHILLIPS^59135" ^WHEAIPP(1,166,1)=2 ^WHEAIPP(1,166,1,1)="58407^^SMSNARE^58420" 2)="58407^59128^MPHILLIPS^59135" ^WHEAIPP(1,324,1)=2 ^WHEAIPP(1,324,1,1)="58884^^SSNARE^58948" 2)="58884^59128^MPHILLIPS^59135" ^WHEAIPP(1,419,1)=3 ^WHEAIPP(1,419,1,1)="59707^^SSNARE^59708" 2)="59707^^MPHILLIPS^59910,58000^^^^" 3)="59707^59981^SSNARE^60117,53241^^^^" The first two subscripts of the global (Hmo and Keen) make a unique entry. The third subscript (Seq) has a property (IppLineCount) which is the number of IppLines in the fourth subscript level (Seq2). I create the class WIppProv below which is the parent class: /// <PRE> /// ============================ /// Generated Class Definition /// Table: WMCA_B_IPP_PROV /// Generated by: FXALTMAN /// Generated on: 05/21/2012 13:46:41 /// Generator: XWESTblClsGenV2 /// ---------------------------- /// </PRE> Class XFXA.MCA.WIppProv Extends (%Persistent, %XML.Adaptor) [ ClassType = persistent, Inheritance = right, ProcedureBlock, StorageStrategy = SQLMapping ] { /// .HMO Property Hmo As %Integer; /// .KEEN Property Keen As %Integer; /// .SEQ Property Seq As %String; Property IppLineCount As %Integer; Index iMaster On (Hmo, Keen, Seq) [ IdKey, Unique ]; Relationship IppLines As XFXA.MCA.WIppProvLine [ Cardinality = many, Inverse = relWIppProv ]; <Storage name="SQLMapping"> <DataLocation>^WHEAIPP</DataLocation> <ExtentSize>1000000</ExtentSize> <SQLMap name="DBMS"> <Data name="IppLineCount"> <Delimiter>"^"</Delimiter> <Node>+0</Node> <Piece>1</Piece> </Data> <Global>^WHEAIPP</Global> <PopulationType>full</PopulationType> <Subscript name="1"> <AccessType>Sub</AccessType> <Expression>{Hmo}</Expression> <LoopInitValue>1</LoopInitValue> </Subscript> <Subscript name="2"> <AccessType>Sub</AccessType> <Expression>{Keen}</Expression> </Subscript> <Subscript name="3"> <AccessType>Sub</AccessType> <LoopInitValue>1</LoopInitValue> <Expression>{Seq}</Expression> </Subscript> <Type>data</Type> </SQLMap> <StreamLocation>^XFXA.MCA.WIppProvS</StreamLocation> <Type>%Library.CacheSQLStorage</Type> </Storage> } This class compiles fine. Next I created the WIppProvLine class listed below and made a parent-child relationship between the two: /// Used to represent a single line of IPP data Class XFXA.MCA.WIppProvLine Extends (%Persistent, %XML.Adaptor) [ ClassType = persistent, Inheritance = right, ProcedureBlock, StorageStrategy = SQLMapping ] { /// .CLM_AMT_ALLOWED node: 0 piece: 6<BR> /// This field should be used in conjunction with the Claim Operator field to /// define a whole claim dollar amount at which a particular claim should be /// flagged with a Pend status. Property ClmAmtAllowed As %String; /// .CLM_LINE_AMT_ALLOWED node: 0 piece: 8<BR> /// This field should be used in conjunction with the Clm Line Operator field to /// define a claim line dollar amount at which a particular claim should be flagged /// with a Pend status. Property ClmLineAmtAllowed As %String; /// .CLM_LINE_OP node: 0 piece: 7<BR> /// A new Table/Column Reference that gives the SIU (Special Investigative Unit) /// the ability to look for claim line dollars above, below, or equal to a set /// amount. Property ClmLineOp As %String; /// .CLM_OP node: 0 piece: 5<BR> /// A new Table/Column Reference that gives the SIU (Special Investigative Unit) /// the ability to look for claim dollars above, below, or equal to a set amount. Property ClmOp As %String; Property EffDt As %Date; Property Hmo As %Integer; /// .IPP_REASON node: 0 piece: 10<BR> /// IPP Reason Code Property IppCode As %Integer; Property Keen As %Integer; /// .LAST_CHG_DT node: 0 piece: 4<BR> /// Last Changed Date Property LastChgDt As %Date; /// .PX_DX_CDE_FLAG node: 0 piece: 9<BR> /// A Flag to indicate whether or not Procedure Codes or Diagnosis Codes are to be /// associated with this SIU Flag Type Entry. If the Flag = Y, then control would /// jump to a new screen where the user can enter the necessary codes. Property PxDxCdeFlag As %String; Property Seq As %String; Property Seq2 As %String; Index iMaster On (Hmo, Keen, Seq, Seq2) [ IdKey, PrimaryKey, Unique ]; /// .TERM_DT node: 0 piece: 2<BR> /// Term Date Property TermDt As %Date; /// .USER_INI node: 0 piece: 3 Property UserIni As %String; Relationship relWIppProv As XFXA.MCA.WIppProv [ Cardinality = one, Inverse = IppLines ]; Index relWIppProvIndex On relWIppProv; //Index NewIndex1 On (RelWIppProv, Seq2) [ IdKey, PrimaryKey, Unique ]; <Storage name="SQLMapping"> <ExtentSize>1000000</ExtentSize> <SQLMap name="DBMS"> <ConditionalWithHostVars></ConditionalWithHostVars> <Data name="ClmAmtAllowed"> <Delimiter>"^"</Delimiter> <Node>+0</Node> <Piece>6</Piece> </Data> <Data name="ClmLineAmtAllowed"> <Delimiter>"^"</Delimiter> <Node>+0</Node> <Piece>8</Piece> </Data> <Data name="ClmLineOp"> <Delimiter>"^"</Delimiter> <Node>+0</Node> <Piece>7</Piece> </Data> <Data name="ClmOp"> <Delimiter>"^"</Delimiter> <Node>+0</Node> <Piece>5</Piece> </Data> <Data name="EffDt"> <Delimiter>"^"</Delimiter> <Node>+0</Node> <Piece>1</Piece> </Data> <Data name="Hmo"> <Delimiter>"^"</Delimiter> <Node>+0</Node> <Piece>11</Piece> </Data> <Data name="IppCode"> <Delimiter>"^"</Delimiter> <Node>+0</Node> <Piece>10</Piece> </Data> <Data name="LastChgDt"> <Delimiter>"^"</Delimiter> <Node>+0</Node> <Piece>4</Piece> </Data> <Data name="PxDxCdeFlag"> <Delimiter>"^"</Delimiter> <Node>+0</Node> <Piece>9</Piece> </Data> <Data name="TermDt"> <Delimiter>"^"</Delimiter> <Node>+0</Node> <Piece>2</Piece> </Data> <Data name="UserIni"> <Delimiter>"^"</Delimiter> <Node>+0</Node> <Piece>3</Piece> </Data> <Global>^WHEAIPP</Global> <Subscript name="1"> <AccessType>Sub</AccessType> <Expression>{Hmo}</Expression> <LoopInitValue>1</LoopInitValue> </Subscript> <Subscript name="2"> <AccessType>Sub</AccessType> <Expression>{Keen}</Expression> <LoopInitValue>1</LoopInitValue> </Subscript> <Subscript name="3"> <AccessType>Sub</AccessType> <Expression>{Seq}</Expression> <LoopInitValue>1</LoopInitValue> </Subscript> <Subscript name="4"> <AccessType>Sub</AccessType> <Expression>{Seq2}</Expression> <LoopInitValue>1</LoopInitValue> </Subscript> <Type>data</Type> </SQLMap> <StreamLocation>^XFXA.MCA.WIppProvLineS</StreamLocation> <Type>%Library.CacheSQLStorage</Type> </Storage> } When I try to compile this one I get the following error: ERROR #5502: Error compiling SQL Table 'XFXA_MCA.WIppProvLine %msg: Table XFXA_MCA.WIppProvLine has the following unmapped (not defined on the data map) fields: relWIppProv' ERROR #5030: An error occurred while compiling class XFXA.MCA.WIppProvLine Detected 1 errors during compilation in 2.745s. What am I doing wrong? Thanks in Advance, Fred

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  • Copy vector of values to vector of pairs in one line

    - by Kirill V. Lyadvinsky
    I have the following types: struct X { int x; X( int val ) : x(val) {} }; struct X2 { int x2; X2() : x2() {} }; typedef std::pair<X, X2> pair_t; typedef std::vector<pair_t> pairs_vec_t; typedef std::vector<X> X_vec_t; I need to initialize instance of pairs_vec_t with values from X_vec_t. I use the following code and it works as expected: int main() { pairs_vec_t ps; X_vec_t xs; // this is not empty in the production code ps.reserve( xs.size() ); { // I want to change this block to one line code. struct get_pair { pair_t operator()( const X& value ) { return std::make_pair( value, X2() ); } }; std::transform( xs.begin(), xs.end(), back_inserter(ps), get_pair() ); } return 0; } What I'm trying to do is to reduce my copying block to one line with using boost::bind. This code is not working: for_each( xs.begin(), xs.end(), boost::bind( &pairs_vec_t::push_back, ps, boost::bind( &std::make_pair, _1, X2() ) ) ); I know why it is not working, but I want to know how to make it working without declaring extra functions and structs?

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  • Python: Best way to check for Python version in program that uses new language features?

    - by Mark Harrison
    If I have a python script that requires at least a particular version of python, what is the correct way to fail gracefully when an earlier version of python is used to launch the script? How do I get control early enough to issue an error message and exit? For example, I have a program that uses the ternery operator (new in 2.5) and "with" blocks (new in 2.6). I wrote a simple little interpreter-version checker routine which is the first thing the script would call ... except it doesn't get that far. Instead, the script fails during python compilation, before my routines are even called. Thus the user of the script sees some very obscure synax error tracebacks - which pretty much require an expert to deduce that it is simply the case of running the wrong version of python. update I know how to check the version of python. The issue is that some syntax is illegal in older versions of python. Consider this program: import sys if sys.version_info < (2, 4): raise "must use python 2.5 or greater" else: # syntax error in 2.4, ok in 2.5 x = 1 if True else 2 print x When run under 2.4, I want this result $ ~/bin/python2.4 tern.py must use python2.5 or greater and not this result: $ ~/bin/python2.4 tern.py File "tern.py", line 5 x = 1 if True else 2 ^ SyntaxError: invalid syntax (channeling for a coworker)

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  • Simple way to repeat a String in java

    - by e5
    I'm looking for a simple commons method or operator that allows me to repeat some String n times. I know I could write this using a for loop, but I wish to avoid for loops whenever necessary and a simple direct method should exist somewhere. String str = "abc"; String repeated = str.repeat(3); repeated.equals("abcabcabc"); Related to: repeat string javascript Create NSString by repeating another string a given number of times Edited I try to avoid for loops when they are not completely necessary because: They add to the number of lines of code even if they are tucked away in another function. Someone reading my code has to figure out what I am doing in that for loop. Even if it is commented and has meaningful variables names, they still have to make sure it is not doing anything "clever". Programmers love to put clever things in for loops, even if I write it to "only do what it is intended to do", that does not preclude someone coming along and adding some additional clever "fix". They are very often easy to get wrong. For loops that involving indexes tend to generate off by one bugs. For loops often reuse the same variables, increasing the chance of really hard to find scoping bugs. For loops increase the number of places a bug hunter has to look.

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  • Binder and variadic template ends up in a segmentation fault

    - by phlipsy
    I wrote the following program #include <iostream> template<typename C, typename Res, typename... Args> class bind_class_t { private: Res (C::*f)(Args...); C *c; public: bind_class_t(Res (C::*f)(Args...), C* c) : f(f), c(c) { } Res operator() (Args... args) { return (c->*f)(args...); } }; template<typename C, typename Res, typename... Args> bind_class_t<C, Res, Args...> bind_class(Res (C::*f)(Args...), C* c) { return bind_class<C, Res, Args...>(f, c); } class test { public: int add(int x, int y) { return x + y; } }; int main() { test t; // bind_class_t<test, int, int, int> b(&test::add, &t); bind_class_t<test, int, int, int> b = bind_class(&test::add, &t); std::cout << b(1, 2) << std::endl; return 0; } compiled it with gcc 4.3.3 and got a segmentation fault. After spending some time with gdb and this program it seems to me that the addresses of the function and the class are mixed up and a call of the data address of the class isn't allowed. Moreover if I use the commented line instead everything works fine. Can anyone else reproduce this behavior and/or explain me what's going wrong here?

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  • Auto-(un)boxing fail for compound assignment

    - by polygenelubricants
    Thanks to the implicit casting in compound assignments and increment/decrement operators, the following compiles: byte b = 0; ++b; b++; --b; b--; b += b -= b *= b /= b %= b; b <<= b >>= b >>>= b; b |= b &= b ^= b; And thanks to auto-boxing and auto-unboxing, the following also compiles: Integer ii = 0; ++ii; ii++; --ii; ii--; ii += ii -= ii *= ii /= ii %= ii; ii <<= ii >>= ii >>>= ii; ii |= ii &= ii ^= ii; And yet, the last line in the following snippet gives compile-time error: Byte bb = 0; ++bb; bb++; --bb; bb--; // ... okay so far! bb += bb; // DOESN'T COMPILE!!! // "The operator += is undefined for the argument type(s) Byte, byte" Can anyone help me figure out what's going on here? The byte b version compiles just fine, so shouldn't Byte bb just follow suit and do the appropriate boxing and unboxing as necessary to accommodate?

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  • jQuery validation plugin - removing elements

    - by d3020
    I'm using the jQuery validation plugin. On most of my input type... tags I have class='required'. When I submit the page, via JavaScript, the controls on the page that have this class are found. However, there are a handful of checkboxes that I don't need to validate. I've tried removing the class code completely from the input tag, also tried class='cancel', and class='required:false. When doing any of those things though when the form submits it can't find the checkbox control. How do I still keep the ability to do Request.Form and find my checkbox object but at the same time when the form submits don't apply validation to this particular control. Thank you. Edit here. This is what I'm using without the "checked" code and ternary operator. In my input tag I'm calling a function like this... sb.Append(" " + crlf); Inside that function is where I check for the True or False coming back, like this. case "chkFlashedCarton": strResultValue = pst.FlashedCarton.ToString(); if (strResultValue == "True") { strResultValue = " checked"; } break; strResultValue is what is returned back. Does this help to see? Thank you.

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  • Abstracting boxed array structures in J

    - by estanford
    I've been working on a J function for a while, that's supposed to scan a list and put consecutive copies of an element into separate, concatenated boxes. My efforts have taken me as far as the function (<;. 2) ((2&(~:/\)),1:) which tests successive list entries for inequality, returns a list of boolean values, and cuts the list into boxes that end each time the number 1 appears. Here's an example application: (<;. 2) ((2&(~:/\)),1:) 1 2 3 3 3 4 1 1 1 +-+-+-----+-+-----+ |1|1|0 0 1|1|0 0 1| +-+-+-----+-+-----+ The task would be finished if I could then replace all those booleans with their corresponding values in the input argument. I've been looking for some kind of mystery function that would let me do something like final =: mysteryfunction @ (<;. 2) ((2&(~:/\)),1:) final 1 2 3 3 3 4 1 1 1 +-+-+-----+-+-----+ |1|2|3 3 3|4|1 1 1| +-+-+-----+-+-----+ In an ideal situation, there would be some way to abstractly represent the nesting pattern generated by (<;. 2) ((2&(~:/\)),1:) to the original input list. (i.e. "This boxed array over here has the first element boxed at depth one, the second element boxed at depth one, the third, fourth, and fifth elements boxed together at depth one,..., so take that unboxed list over there and box it up the same way.") I tried fooling around with ;. , S: , L:, L. and &. to produce that behavior, but I haven't had much luck. Is there some kind of operator or principle I'm missing that could make this happen? It wouldn't surprise me if I were overthinking the whole issue, but I'm running out of ideas.

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  • Pronunciation of programming structures (particularly in c#)

    - by Andrzej Nosal
    As a non-English speaking person I often have problems pronouncing certain programming structures and abbreviations. I've been watching some video tutorials and listening to podcasts as well, though I couldn't catch them all. My question is what is the common or correct pronunciation of the following code snippets? Generics, like IEnumerable<int> or in a method void Swap<T>(T lhs, T rhs) Collections indexing and indexer access e.g. garage[i], rectangular arrays myArray[2,1] or jagged[1][2][3] Lambda operator =>, e.g. in a where extension method .Where(animal => animal.Color == Color.Brown) or in an anonymous method () => { return false;} Inheritance class Derived : Base (extends?) class SomeClass : IDisposable (implements?) Arithemtic operators += -= *= /= %= ! Are += and -= pronounced the same for events? Collections initializers new int[] { 4, 5, 8, 9, 12, 13, 16, 17 }; Casting MyEnum foo = (MyEnum)(int)yourFloat; (as?) Nullables DateTime? dt = new DateTime?(); I tagged the question with C# as some of them are specific to C# only.

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  • Update mapping table in Linq

    - by Gary McGill
    I have a table Customers with a CustomerId field, and a table of Publications with a PublicationId field. Finally, I have a mapping table CustomersPublications that records which publications a customer can access - it has two fields: CustomerId field PublicationId. For a given customer, I want to update the CustomersPublications table based on a list of publication ids. I want to remove records in CustomersPublications where the PublicationId is not in the list, and add new records where the PublicationId is in the list but not already in the table. This would be easy in SQL, but I can't figure out how to do it in Linq. For the delete part, I tried: var recordsToDelete = dataContext.CustomersPublications.Where ( cp => (cp.CustomerId == customerId) && ! publicationIds.Contains(cp.PublicationId) ); dataContext.CustomersPublications.DeleteAllOnSubmit(recordsToDelete); ... but that didn't work. I got an error: System.NotSupportedException: Method 'Boolean Contains(Int32)' has no supported translation to SQL So, I tried using Any(), as follows: var recordsToDelete = dataContext.CustomersPublications.Where ( cp => (cp.CustomerId == customerId) && ! publicationIds.Any(p => p == cp.PublicationId) ); ... and this just gives me another error: System.NotSupportedException: Local sequence cannot be used in LINQ to SQL implementation of query operators except the Contains() operator Any pointers? [I have to say, I find Linq baffling (and frustrating) for all but the simplest queries. Better error messages would help!]

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  • Return a list of imported Python modules used in a script?

    - by Jono Bacon
    Hi All, I am writing a program that categorizes a list of Python files by which modules they import. As such I need to scan the collection of .py files ad return a list of which modules they import. As an example, if one of the files I import has the following lines: import os import sys, gtk I would like it to return: ["os", "sys", "gtk"] I played with modulefinder and wrote: from modulefinder import ModuleFinder finder = ModuleFinder() finder.run_script('testscript.py') print 'Loaded modules:' for name, mod in finder.modules.iteritems(): print '%s ' % name, but this returns more than just the modules used in the script. As an example in a script which merely has: import os print os.getenv('USERNAME') The modules returned from the ModuleFinder script return: tokenize heapq __future__ copy_reg sre_compile _collections cStringIO _sre functools random cPickle __builtin__ subprocess cmd gc __main__ operator array select _heapq _threading_local abc _bisect posixpath _random os2emxpath tempfile errno pprint binascii token sre_constants re _abcoll collections ntpath threading opcode _struct _warnings math shlex fcntl genericpath stat string warnings UserDict inspect repr struct sys pwd imp getopt readline copy bdb types strop _functools keyword thread StringIO bisect pickle signal traceback difflib marshal linecache itertools dummy_thread posix doctest unittest time sre_parse os pdb dis ...whereas I just want it to return 'os', as that was the module used in the script. Can anyone help me achieve this?

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  • How to access empty ASP.NET ListView.ListViewItem to apply a style after all databinding is done?

    - by Caroline S.
    We're using a ListView with a GroupTemplate to create a three-column navigation menu with six items in each column, filling in two non-data-bound rows in the last column with an EmptyItemTemplate that contains an empty HTML list item. That part works fine, but I also need to programmatically add a CSS class to the sixth (last) item in each column. That part is also working fine for the first two columns because I'm assigning the CSS class in the DataBound event, where I can iterate through the ListView.Items collection and access the sixth item in the first two columns by using a modulus operator and counter. The problem comes in the last column, where the EmptyItemTemplate has correctly filled in two empty list items, to the last of which I also need to add this CSS class. The empty items are not included in the ListView.Items collection (that's just ListViewDataItems, and the empty items are ListViewItems). I cannot find a way to access the entire collection of ListViewItems after binding. Am I missing something? I know I can access the empty items during ItemCreated, but I can't figure out how to determine where the item I'm creating falls in the flow, and whether it's the last one. Any help would be appreciated, if this can even be done -- I'm a bit stuck.

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  • can't increment Glib::ustring::iterator (getting "invalid lvalue in increment" compiler error)

    - by davka
    in the following code: int utf8len(char* s, int len) { Glib::ustring::iterator p( string::iterator(s) ); Glib::ustring::iterator e ( string::iterator(s+len) ); int i=0; for (; p != e; p++) // ERROR HERE! i++; return i; } I get the compiler error on the for line, which is sometimes "invalid lvalue in increment", and sometimes "ISO C++ forbids incrementing a pointer of type etc... ". Yet, the follwing code: int utf8len(char* s) { Glib::ustring us(s); int i=0; for (Glib::ustring::iterator p = us.begin(); p != us.end(); p++) i++; return i; } compiles and works fine. according the Glib::ustring documentation and the include file, ustring iterator can be constructed from std::string iterator, and has operator++() defined. Weird? BONUS QUESTION :) Is there a difference in C++ between the 2 ways of defining a variable: classname ob1( initval ); classname ob1 = initval; I believed that they are synonymous; yet, if I change Glib::ustring::iterator p( string::iterator(s) ); to Glib::ustring::iterator p = string::iterator(s); I get a compiler error (gcc 4.1.2) conversion from ‘__gnu_cxx::__normal_iterator, std::allocator ’ to non-scalar type ‘Glib::ustring_Iterator<__gnu_cxx::__normal_iterator, std::allocator ’ requesed thanks a lot!

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