Search Results

Search found 5086 results on 204 pages for 'compiler constants'.

Page 176/204 | < Previous Page | 172 173 174 175 176 177 178 179 180 181 182 183  | Next Page >

• erlide, which eclipse/which packages?

  - by KevinDTimm

  I have downloaded eclipse 3.4 (java version) for MacOSX (carbon). I have tried to 'update' to the erlide, but see many (duplicated) options (many erlide, options that say 'only for erl SDK updates', etc.) Sometimes I get 403 errors when attempting to access http://erlide.org/update and http://erlide.sourceforge.net/update. Finally, when I get some set of options installed, I either get errors like : Loading of /Users/kevindtimm/Documents/eclipse-java-ganymede-SR2-macosx-carbon/eclipse/plugins/org.erlide.kernel.common_0.8.1.201005250801/ebin/erlide_kernel_common.beam failed: badfile (hello_world@ktmac)1> =ERROR REPORT==== 24-Nov-2010::19:17:32 === beam/beam_load.c(1768): Error loading function erlide_kernel_common:monitor/0: op put_string u u x: please re-compile this module with an R14B compiler or, when I've done different installations of erlide, I get no response in the console to : hello:hello(). Does anybody have a good reference for how to load this plug-in and which items I should install? -module(hello). -export([hello/0]). hello() -> io:write("Hello World\n"). [edit] I have installed eclipse 3.6 (c++) as requested below, and the following code still can't find hello:hello(). %%file_comment -module(hello). %% %% Include files %% %% %% Exported Functions %% -export([hello/0]). %% %% API Functions %% %% %% Local Functions %% hello() -> io:write("Hello World\n"). [/edit]

  Read the article

• Java Generics Class Parameter Type Inference

  - by Pindatjuh

  Given the interface: public interface BasedOnOther<T, U extends BasedList<T>> { public T getOther(); public void staticStatisfied(final U list); } The BasedOnOther<T, U extends BasedList<T>> looks very ugly in my use-cases. It is because the T type parameter is already defined in the BasedList<T> part, so the "uglyness" comes from that T needs to be typed twice. Problem: is it possible to let the Java compiler infer the generic T type from BasedList<T> in a generic class/interface definition? Ultimately, I'd like to use the interface like: class X implements BasedOnOther<BasedList<SomeType>> { public SomeType getOther() { ... } public void staticStatisfied(final BasedList<SomeType> list) { ... } } // Does not compile, due to invalid parameter count. Instead: class X implements BasedOnOther<SomeType, BasedList<SomeType>> { public SomeType getOther() { ... } public void staticStatisfied(final BasedList<SomeType> list) { ... } }

  Read the article

• What are the lengths/limits C preprocessor as a language creation tool? Where can I learn more about

  - by Weston C

  In his FAQ @ http://www2.research.att.com/~bs/bs_faq.html#bootstrapping, Bjarne Stroustrup says: To build [Cfront, the first C++ compiler], I first used C to write a "C with Classes"-to-C preprocessor. "C with Classes" was a C dialect that became the immediate ancestor to C++... I then wrote the first version of Cfront in "C with Classes". When I read this, it piqued my interest in the C preprocessor. I'd seen its macro capabilities as suitable for simplifying common expressions but hadn't thought about its ability to significantly add to syntax and semantics on the level that I imagine bringing classes to C took. So now I have a couple of questions on my mind: 1) Are there other examples of this approach to bootstrapping a language off of C? 2) Is the source to Stroustrup's original work available anywhere? 3) Where could I learn more about the specifics of utilizing this technique? 4) What are the lengths/limits of that approach? Could one, say, create a set of preprocessor macros that let someone write in something significantly Lisp/Scheme like?

  Read the article

• Trying to make a plugin system in C++/Qt

  - by Pirate for Profit

  I'm making a task-based program that needs to have plugins. Tasks need to have properties which can be easily edited, I think this can be done with Qt's Meta-Object Compiler reflection capabilities (I could be wrong, but I should be able to stick this in a QtPropertyBrowser?) So here's the base: class Task : public QObject { Q_OBJECT public: explicit Task(QObject *parent = 0) : QObject(parent){} virtual void run() = 0; signals: void taskFinished(bool success = true); } Then a plugin might have this task: class PrinterTask : public Task { Q_OBJECT public: explicit PrinterTask(QObject *parent = 0) : Task(parent) {} void run() { Printer::getInstance()->Print(this->getData()); // fictional emit taskFinished(true); } inline const QString &getData() const; inline void setData(QString data); Q_PROPERTY(QString data READ getData WRITE setData) // for reflection } In a nutshell, here's what I want to do: // load plugin // find all the Tasks interface implementations in it // have user able to choose a Task and edit its specific Q_PROPERTY's // run the TASK It's important that one .dll has multiple tasks, because I want them to be associated by their module. For instance, "FileTasks.dll" could have tasks for deleting files, making files, etc. The only problem with Qt's plugin setup is I want to store X amount of Tasks in one .dll module. As far as I can tell, you can only load one interface per plugin (I could be wrong?). If so, the only possible way to do accomplish what I want is to create a FactoryInterface with string based keys which return the objects (as in Qt's Plug-And-Paint example), which is a terrible boilerplate that I would like to avoid. Anyone know a cleaner C++ plugin architecture than Qt's to do what I want? Also, am I safely assuming Qt's reflection capabilities will do what I want (i.e. able to edit an unknown dynamically loaded tasks' properties with the QtPropertyBrowser before dispatching)?

  Read the article

• C++ casted realloc causing memory leak

  - by wyatt

  I'm using a function I found here to save a webpage to memory with cURL: struct WebpageData { char *pageData; size_t size; }; size_t storePage(void *input, size_t size, size_t nmemb, void *output) { size_t realsize = size * nmemb; struct WebpageData *page = (struct WebpageData *)output; page->pageData = (char *)realloc(page->pageData, page->size + realsize + 1); if(page->pageData) { memcpy(&(page->pageData[page->size]), input, realsize); page->size += realsize; page->pageData[page->size] = 0; } return realsize; } and find the line: page->pageData = (char *)realloc(page->pageData, page->size + realsize + 1); is causing a memory leak of a few hundred bytes per call. The only real change I've made from the original source is casting the line in question to a (char *), which my compiler (gcc, g++ specifically if it's a c/c++ issue, but gcc also wouldn't compile with the uncast statement) insisted upon, but I assume this is the source of the leak. Can anyone elucidate? Thanks

  Read the article

• Abstract base class puzzle

  - by 0x80

  In my class design I ran into the following problem: class MyData { int foo; }; class AbstraktA { public: virtual void A() = 0; }; class AbstraktB : public AbstraktA { public: virtual void B() = 0; }; template<class T> class ImplA : public AbstraktA { public: void A(){ cout << "ImplA A()"; } }; class ImplB : public ImplA<MyData>, public AbstraktB { public: void B(){ cout << "ImplB B()"; } }; void TestAbstrakt() { AbstraktB *b = (AbstraktB *) new ImplB; b->A(); b->B(); }; The problem with the code above is that the compiler will complain that AbstraktA::A() is not defined. Interface A is shared by multiple objects. But the implementation of A is dependent on the template argument. Interface B is the seen by the outside world, and needs to be abstrakt. The reason I would like this is that it would allow me to define object C like this: Define the interface C inheriting from abstrakt A. Define the implementation of C using a different datatype for template A. I hope I'm clear. Is there any way to do this, or do I need to rethink my design?

  Read the article

• How do I make my ArrayList Thread-Safe? Another approach to problem in Java?

  - by thechiman

  I have an ArrayList that I want to use to hold RaceCar objects that extend the Thread class as soon as they are finished executing. A class, called Race, handles this ArrayList using a callback method that the RaceCar object calls when it is finished executing. The callback method, addFinisher(RaceCar finisher), adds the RaceCar object to the ArrayList. This is supposed to give the order in which the Threads finish executing. I know that ArrayList isn't synchronized and thus isn't thread-safe. I tried using the Collections.synchronizedCollection(c Collection) method by passing in a new ArrayList and assigning the returned Collection to an ArrayList. However, this gives me a compiler error: Race.java:41: incompatible types found : java.util.Collection required: java.util.ArrayList finishingOrder = Collections.synchronizedCollection(new ArrayList(numberOfRaceCars)); Here is the relevant code: public class Race implements RaceListener { private Thread[] racers; private ArrayList finishingOrder; //Make an ArrayList to hold RaceCar objects to determine winners finishingOrder = Collections.synchronizedCollection(new ArrayList(numberOfRaceCars)); //Fill array with RaceCar objects for(int i=0; i<numberOfRaceCars; i++) { racers[i] = new RaceCar(laps, inputs[i]); //Add this as a RaceListener to each RaceCar ((RaceCar) racers[i]).addRaceListener(this); } //Implement the one method in the RaceListener interface public void addFinisher(RaceCar finisher) { finishingOrder.add(finisher); } What I need to know is, am I using a correct approach and if not, what should I use to make my code thread-safe? Thanks for the help!

  Read the article

• how to store a file handle in perl class

  - by Haiyuan Zhang

  please look at the following code first. #! /usr/bin/perl package foo; sub new { my $pkg = shift; my $self = {}; my $self->{_fd} = undef; bless $self, $pkg; return $self; } sub Setfd { my $self = shift; my $fd = shift; $self_->{_fd} = $fd; } sub write { my $self = shift; print $self->{_fd} "hello word"; } my $foo = new foo; My intention is to store a file handle within a class using hash. the file handle is undefined at first, but can be initilized afterwards by calling Setfd function. then write can be called to actually write string "hello word" to a file indicated by the file handle, supposed that the file handle is the result of a success "write" open. but, perl compiler just complains that there are syntax error in the "print" line. can anyone of you tells me what's wrong here? thanks in advance.

  Read the article

• Why does GCC need extra declarations in templates when VS does not?

  - by Kyle

  template<typename T> class Base { protected: Base() {} T& get() { return t; } T t; }; template<typename T> class Derived : public Base<T> { public: Base<T>::get; // Line A Base<T>::t; // Line B void foo() { t = 4; get(); } }; int main() { return 0; } If I comment out lines A and B, this code compiles fine under Visual Studio 2008. Yet when I compile under GCC 4.1 with lines A and B commented, I get these errors: In member function ‘void TemplateDerived::foo()’: error: ‘t’ was not declared in this scope error: there are no arguments to ‘get’ that depend on a template parameter, so a declaration of ‘get’ must be available Why would one compiler require lines A and B while the other doesn't? Is there a way to simplify this? In other words, if derived classes use 20 things from the base class, I have to put 20 lines of declarations for every class deriving from Base! Is there a way around this that doesn't require so many declarations?

  Read the article

• adding virtual function to the end of the class declaration avoids binary incompatibility?

  - by bob

  Could someone explain to me why adding a virtual function to the end of a class declaration avoids binary incompatibility? If I have: class A { public: virtual ~A(); virtual void someFuncA() = 0; virtual void someFuncB() = 0; virtual void other1() = 0; private: int someVal; }; And later modify this function to: class A { public: virtual ~A(); virtual void someFuncA(); virtual void someFuncB(); virtual void someFuncC(); virtual void other1() = 0; private: int someVal; }; I get a coredump from another .so compiled against the previous declaration. But if I put someFuncC() at the end of the class declaration (after "int someVal"), I don't see coredump anymore. Could someone tell me why this is? And does this trick always work? PS. compiler is gcc, does this work with other compilers?

  Read the article

• C++ Implicit Conversion Operators

  - by Imbue

  I'm trying to find a nice inheritance solution in C++. I have a Rectangle class and a Square class. The Square class can't publicly inherit from Rectangle, because it cannot completely fulfill the rectangle's requirements. For example, a Rectangle can have it's width and height each set separately, and this of course is impossible with a Square. So, my dilemma. Square obviously will share a lot of code with Rectangle; they are quite similar. For examlpe, if I have a function like: bool IsPointInRectangle(const Rectangle& rect); it should work for a square too. In fact, I have a ton of such functions. So in making my Square class, I figured I would use private inheritance with a publicly accessible Rectangle conversion operator. So my square class looks like: class Square : private Rectangle { public: operator const Rectangle&() const; }; However, when I try to pass a Square to the IsPointInRectangle function, my compiler just complains that "Rectangle is an inaccessible base" in that context. I expect it to notice the Rectangle operator and use that instead. Is what I'm trying to do even possible? If this can't work I'm probably going to refactor part of Rectangle into MutableRectangle class. Thanks.

  Read the article

• Why is TRest in Tuple<T1... TRest> not constrained?

  - by Anthony Pegram

  In a Tuple, if you have more than 7 items, you can provide an 8th item that is another tuple and define up to 7 items, and then another tuple as the 8th and on and on down the line. However, there is no constraint on the 8th item at compile time. For example, this is legal code for the compiler: var tuple = new Tuple<int, int, int, int, int, int, int, double> (1, 1, 1, 1, 1, 1, 1, 1d); Even though the intellisense documentation says that TRest must be a Tuple. You do not get any error when writing or building the code, it does not manifest until runtime in the form of an ArgumentException. You can roughly implement a Tuple in a few minutes, complete with a Tuple-constrained 8th item. I just wonder why it was left off the current implementation? Is it possibly a forward-compatibility issue where they could add more elements with a hypothetical C# 5? Short version of rough implementation interface IMyTuple { } class MyTuple<T1> : IMyTuple { public T1 Item1 { get; private set; } public MyTuple(T1 item1) { Item1 = item1; } } class MyTuple<T1, T2> : MyTuple<T1> { public T2 Item2 { get; private set; } public MyTuple(T1 item1, T2 item2) : base(item1) { Item2 = item2; } } class MyTuple<T1, T2, TRest> : MyTuple<T1, T2> where TRest : IMyTuple { public TRest Rest { get; private set; } public MyTuple(T1 item1, T2 item2, TRest rest) : base(item1, item2) { Rest = rest; } } ... var mytuple = new MyTuple<int, int, MyTuple<int>>(1, 1, new MyTuple<int>(1)); // legal var mytuple2 = new MyTuple<int, int, int>(1, 2, 3); // illegal

  Read the article

• not able to run c/cpp execs in eclipse cdt

  - by user1658323

  i installed eclipse and then cdt on an ubuntu system recently and was trying to make the first runnable c/c++ proj.. i installed g++ also, and then created the first executable cpp 'Hello World' project some files are created... then some issues... 1) even though Build Automatically is selected, I have to goto the project n do a Build Project to build it manually, and this i have to do everytime i make a change 2) After Building manually, there are some new folders created with Binaries and Debug files and i can see g++ commands in the console being executed. The project binary is output both to debug n binaries folder. But i am not able to run these through the Green Play Button or any other way in eclipse. Even Run configuration is not showing any option for c/C++ proj.. though i can goto terminal and run the binary myself through ./ But i want to be able to run n debug this through eclipse. plz help in fixing me this problem as i really love eclipse n have some c/cpp assignments coming soon.. Console info on doing a manual project build - Build of configuration Debug for project qwe ** make all Building file: ../src/qwe.cpp Invoking: GCC C++ Compiler g++ -O0 -g3 -Wall -c -fmessage-length=0 -MMD -MP -MF"src/qwe.d" -MT"src/qwe.d" -o "src/qwe.o" "../src/qwe.cpp" Finished building: ../src/qwe.cpp Building target: qwe Invoking: GCC C++ Linker g++ -o "qwe" ./src/qwe.o Finished building target: qwe Build Finished **

  Read the article

• Alternatives to static methods on interfaces for enforcing consistency

  - by jayshao

  In Java, I'd like to be able to define marker interfaces, that forced implementations to provide static methods. For example, for simple text-serialization/deserialization I'd like to be able to define an interface that looked something like this: public interface TextTransformable<T>{ public static T fromText(String text); public String toText(); Since interfaces in Java can't contain static methods though (as noted in a number of other posts/threads: here, here, and here this code doesn't work. What I'm looking for however is some reasonable paradigm to express the same intent, namely symmetric methods, one of which is static, and enforced by the compiler. Right now the best we can come up with is some kind of static factory object or generic factory, neither of which is really satisfactory. Note: in our case our primary use-case is we have many, many "value-object" types - enums, or other objects that have a limited number of values, typically carry no state beyond their value, and which we parse/de-parse thousands of time a second, so actually do care about reusing instances (like Float, Integer, etc.) and its impact on memory consumption/g.c. Any thoughts?

  Read the article

• On C++ global operator new: why it can be replaced

  - by Jimmy

  I wrote a small program in VS2005 to test whether C++ global operator new can be overloaded. It can. #include "stdafx.h" #include "iostream" #include "iomanip" #include "string" #include "new" using namespace std; class C { public: C() { cout<<"CTOR"<<endl; } }; void * operator new(size_t size) { cout<<"my overload of global plain old new"<<endl; // try to allocate size bytes void *p = malloc(size); return (p); } int main() { C* pc1 = new C; cin.get(); return 0; } In the above, my definition of operator new is called. If I remove that function from the code, then operator new in C:\Program Files (x86)\Microsoft Visual Studio 8\VC\crt\src\new.cpp gets called. All is good. However, in my opinion, my implementations of operator new does NOT overload the new in new.cpp, it CONFLICTS with it and violates the one-definition rule. Why doesn't the compiler complain about it? Or does the standard say since operator new is so special, one-definition rule does not apply here? Thanks.

  Read the article

• Java Generics Class Type Parameter Inference

  - by Pindatjuh

  Given the interface: public interface BasedOnOther<T, U extends BasedList<T>> { public T getOther(); public void staticStatisfied(final U list); } The BasedOnOther<T, U extends BasedList<T>> looks very ugly in my use-cases. It is because the T type parameter is already defined in the BasedList<T> part, so the "uglyness" comes from that T needs to be typed twice. Problem: is it possible to let the Java compiler infer the generic T type from BasedList<T> in a generic class/interface definition? Ultimately, I'd like to use the interface like: class X extends BasedOnOther<BasedList<SomeType>> { public SomeType getOther() { ... } public void staticStatisfied(final BasedList<SomeType> list) { ... } } Instead: class X extends BasedOnOther<SomeType, BasedList<SomeType>> { public SomeType getOther() { ... } public void staticStatisfied(final BasedList<SomeType> list) { ... } }

  Read the article

• How are two-dimensional arrays formatted in memory?

  - by Chris Cooper

  In C, I know I can dynamically allocate a two-dimensional array on the heap using the following code: int** someNumbers = malloc(arrayRows*sizeof(int*)); for (i = 0; i < arrayRows; i++) { someNumbers[i] = malloc(arrayColumns*sizeof(int)); } Clearly, this actually creates a one-dimensional array of pointers to a bunch of separate one-dimensional arrays of integers, and "The System" can figure you what I mean when I ask for: someNumbers[4][2]; But when I statically declare a 2D array, as in the following line...: int someNumbers[ARRAY_ROWS][ARRAY_COLUMNS]; ...does a similar structure get created on the stack, or is it of another form completely? (i.e. is it a 1D array of pointers? If not, what is it, and how do references to it get figured out?) Also, when I said, "The System," what is actually responsible for figuring that out? The kernel? Or does the C compiler sort it out while compiling?

  Read the article

• Why is Func<T> ambiguous with Func<IEnumerable<T>>?

  - by Matt Hamilton

  This one's got me flummoxed, so I thought I'd ask here in the hope that a C# guru can explain it to me. Why does this code generate an error? class Program { static void Main(string[] args) { Foo(X); // the error is on this line } static String X() { return "Test"; } static void Foo(Func<IEnumerable<String>> x) { } static void Foo(Func<String> x) { } } The error in question: Error 1 The call is ambiguous between the following methods or properties: 'ConsoleApplication1.Program.Foo(System.Func<System.Collections.Generic.IEnumerable<string>>)' and 'ConsoleApplication1.Program.Foo(System.Func<string>)' C:\Users\mabster\AppData\Local\Temporary Projects\ConsoleApplication1\Program.cs 12 13 ConsoleApplication1 It doesn't matter what type I use - if you replace the "String" declarations with "int" in that code you'll get the same sort of error. It's like the compiler can't tell the difference between Func<T> and Func<IEnumerable<T>>. Can someone shed some light on this?

  Read the article

• Native Endians and Auto Conversion

  - by KnickerKicker

  so the following converts big endians to little ones uint32_t ntoh32(uint32_t v) { return (v << 24) | ((v & 0x0000ff00) << 8) | ((v & 0x00ff0000) >> 8) | (v >> 24); } works. like a charm. I read 4 bytes from a big endian file into char v[4] and pass it into the above function as ntoh32 (* reinterpret_cast<uint32_t *> (v)) that doesn't work - because my compiler (VS 2005) automatically converts the big endian char[4] into a little endian uint32_t when I do the cast. AFAIK, this automatic conversion will not be portable, so I use uint32_t ntoh_4b(char v[]) { uint32_t a = 0; a |= (unsigned char)v[0]; a <<= 8; a |= (unsigned char)v[1]; a <<= 8; a |= (unsigned char)v[2]; a <<= 8; a |= (unsigned char)v[3]; return a; } yes the (unsigned char) is necessary. yes it is dog slow. there must be a better way. anyone ?

  Read the article

• multiple definition in header file

  - by Jérôme

  Here is a small code-example from which I'd like to ask a question : complex.h : #ifndef COMPLEX_H #define COMPLEX_H #include <iostream> class Complex { public: Complex(float Real, float Imaginary); float real() const { return m_Real; }; private: friend std::ostream& operator<<(std::ostream& o, const Complex& Cplx); float m_Real; float m_Imaginary; }; std::ostream& operator<<(std::ostream& o, const Complex& Cplx) { return o << Cplx.m_Real << " i" << Cplx.m_Imaginary; } #endif // COMPLEX_H complex.cpp : #include "complex.h" Complex::Complex(float Real, float Imaginary) { m_Real = Real; m_Imaginary = Imaginary; } main.cpp : #include "complex.h" #include <iostream> int main() { Complex Foo(3.4, 4.5); std::cout << Foo << "\n"; return 0; } When compiling this code, I get the following error : multiple definition of operator<<(std::ostream&, Complex const&) I've found that making this fonction inline solves the problem, but I don't understand why. Why does the compiler complain about multiple definition ? My header file is guarded (with #define COMPLEX_H). And, if complaining about the operator<< fonction, why not complain about the public real() fonction, which is defined in the header as well ? And is there another solution as using the inline keyword ?

  Read the article

• map operator [] operands

  - by Jamie Cook

  Hi all I have the following in a member function int tt = 6; vector<set<int>>& temp = m_egressCandidatesByDestAndOtMode[tt]; set<int>& egressCandidateStops = temp.at(dest); and the following declaration of a member variable map<int, vector<set<int>>> m_egressCandidatesByDestAndOtMode; However I get an error when compiling (Intel Compiler 11.0) 1>C:\projects\svn\bdk\Source\ZenithAssignment\src\Iteration\PtBranchAndBoundIterationOriginRunner.cpp(85): error: no operator "[]" matches these operands 1> operand types are: const std::map<int, std::vector<std::set<int, std::less<int>, std::allocator<int>>, std::allocator<std::set<int, std::less<int>, std::allocator<int>>>>, std::less<int>, std::allocator<std::pair<const int, std::vector<std::set<int, std::less<int>, std::allocator<int>>, std::allocator<std::set<int, std::less<int>, std::allocator<int>>>>>>> [ const int ] 1> vector<set<int>>& temp = m_egressCandidatesByDestAndOtMode[tt]; 1> ^ I know it's got to be something silly but I can't see what I've done wrong.

  Read the article

• Does C# allow method overloading, PHP style (__call)?

  - by mr.b

  In PHP, there is a special method named __call($calledMethodName, $arguments), which allows class to catch calls to non-existing methods, and do something about it. Since most of classic languages are strongly typed, compiler won't allow calling a method that does not exist, I'm clear with that part. What I want to accomplish (and I figured this is how I would do it in PHP, but C# is something else) is to proxy calls to a class methods and log each of these calls. Right now, I have code similar to this: class ProxyClass { static logger; public AnotherClass inner { get; private set; } public ProxyClass() { inner = new AnotherClass(); } } class AnotherClass { public void A() {} public void B() {} public void C() {} // ... } // meanwhile, in happyCodeLandia... ProxyClass pc = new ProxyClass(); pc.inner.A(); pc.inner.B(); // ... So, how can I proxy calls to an object instance in extensible way? Extensible, meaning that I don't have to modify ProxyClass whenever AnotherClass changes. In my case, AnotherClass can have any number of methods, so it wouldn't be appropriate to overload or wrap all methods to add logging. I am aware that this might not be the best approach for this kind of problem, so if anyone has idea what approach to use, shoot. Thanks!

  Read the article

• User defined literal arguments are not constexpr?

  - by Pubby

  I'm testing out user defined literals. I want to make _fac return the factorial of the number. Having it call a constexpr function works, however it doesn't let me do it with templates as the compiler complains that the arguments are not and cannot be constexpr. I'm confused by this - aren't literals constant expressions? The 5 in 5_fac is always a literal that can be evaluated during compile time, so why can't I use it as such? First method: constexpr int factorial_function(int x) { return (x > 0) ? x * factorial_function(x - 1) : 1; } constexpr int operator "" _fac(unsigned long long x) { return factorial_function(x); // this works } Second method: template <int N> struct factorial { static const unsigned int value = N * factorial<N - 1>::value; }; template <> struct factorial<0> { static const unsigned int value = 1; }; constexpr int operator "" _fac(unsigned long long x) { return factorial_template<x>::value; // doesn't work - x is not a constexpr }

  Read the article

• what is meant by normalization in huge pointers

  - by wrapperm

  Hi, I have a lot of confusion on understanding the difference between a "far" pointer and "huge" pointer, searched for it all over in google for a solution, couldnot find one. Can any one explain me the difference between the two. Also, what is the exact normalization concept related to huge pointers. Please donot give me the following or any similar answers: "The only difference between a far pointer and a huge pointer is that a huge pointer is normalized by the compiler. A normalized pointer is one that has as much of the address as possible in the segment, meaning that the offset is never larger than 15. A huge pointer is normalized only when pointer arithmetic is performed on it. It is not normalized when an assignment is made. You can cause it to be normalized without changing the value by incrementing and then decrementing it. The offset must be less than 16 because the segment can represent any value greater than or equal to 16 (e.g. Absolute address 0x17 in a normalized form would be 0001:0001. While a far pointer could address the absolute address 0x17 with 0000:0017, this is not a valid huge (normalized) pointer because the offset is greater than 0000F.). Huge pointers can also be incremented and decremented using arithmetic operators, but since they are normalized they will not wrap like far pointers." Here the normalization concept is not very well explained, or may be I'm unable to understand it very well. Can anyone try explaining this concept from a beginners point of view. Thanks, Rahamath

  Read the article

• How can I modified the value of a string defined in a struc?

  - by Eric

  Hi, I have the following code in c++: define TAM 4000 define NUMPAGS 512 struct pagina { bitset<12 direccion; char operacion; char permiso; string *dato; int numero; }; void crearPagina(pagina* pag[], int pos, int dir) { pagina * paginas = (pagina*)malloc(sizeof(char) * TAM); paginas - direccion = bitset<12 (dir); paginas - operacion = 'n'; paginas - permiso = 'n'; string **tempDato = &paginas - dato; char *temp = " "; **tempDato = temp; paginas - numero = 0; pag[pos] = paginas; } I want to modify the value of the variable called "string *dato" in the struct pagina but, everytime I want to assing a new value, the compiler throws a segmentation fault. In this case I'm using a pointer to string, but I have also tried with a string. In a few words I want to do the following: pagina - dato = "test"; Any idea? Thanks in advance!!!

  Read the article

< Previous Page | 172 173 174 175 176 177 178 179 180 181 182 183  | Next Page >