Search Results

Search found 37882 results on 1516 pages for 'function overloading'.

Page 47/1516 | < Previous Page | 43 44 45 46 47 48 49 50 51 52 53 54  | Next Page >

• How do boost operators work?

  - by FredOverflow

  boost::operators automatically defines operators like + based on manual implementations like += which is very useful. To generate those operators for T, one inherits from boost::operators<T> as shown by the boost example: class MyInt : boost::operators<MyInt> I am familiar with the CRTP pattern, but I fail to see how it works here. Specifically, I am not really inheriting any facilities since the operators aren't members. boost::operators seems to be completely empty, but I'm not very good at reading boost source code. Could anyone explain how this works in detail? Is this mechanism well-known and widely used?

  Read the article

• jQuery $.ajax success must be a callback function?

  - by b. e. hollenbeck

  I've created a wrapper function for jQuery's $.ajax() method so I can pass different dataTypes and post variables - like so: function doPost(dType, postData, uri){ $.ajax({ url: SITE_URL + uri, dataType: dType, data: postData, success: function(data){ return data; }); } The problem I'm having is getting the data (which is always JSON) back out. I've tried setting a var ret before the $.ajax() function call and setting it as ret = data in the success function. Am I being stupid about this? If I don't set a success function, will the $.ajax simply return the data? Or is it just success: return data? Or does success require a callback function to handle the data, which could just be return data?

  Read the article

• overloaded stream insertion operator with a vector

  - by Julz

  hi, i'm trying to write an overloaded stream insertion operator for a class who's only member is a vector. i dont really know what i'm doing. (lets make that clear) it's a vector of "Points" which is a struct containing two doubles. i figure what i want is to insert user input (a bunch of doubles) into a stream that i then send to a modifier method? i keep working off other stream insertion examples such as... std::ostream& operator<< (std::ostream& o, Fred const& fred) { return o << fred.i_; } but when i try a similar..... istream & operator >> (istream &inStream, Polygon &vertStr) { inStream >> ws; inStream >> vertStr.vertices; return inStream; } i get an error "no match for operator etc etc. if i leave off the .vertices it compiles but i figure it's not right? (vertices is the name of my vector ) and even if it is right, i dont actually know what syntax to use in my driver to use it? also not %100 on what my modifier method needs to look like. here's my Polygon class //header #ifndef POLYGON_H #define POLYGON_H #include "Segment.h" #include <vector> class Polygon { friend std::istream & operator >> (std::istream &inStream, Polygon &vertStr); public: //Constructor Polygon(const Point &theVerts); //Default Constructor Polygon(); //Copy Constructor Polygon(const Polygon &polyCopy); //Accessor/Modifier methods inline std::vector<Point> getVector() const {return vertices;} //Return number of Vector elements inline int sizeOfVect() const {return (int) vertices.capacity();} //add Point elements to vector inline void setVertices(const Point &theVerts){vertices.push_back (theVerts);} private: std::vector<Point> vertices; }; #endif //Body using namespace std; #include "Polygon.h" // Constructor Polygon::Polygon(const Point &theVerts) { vertices.push_back (theVerts); } //Copy Constructor Polygon::Polygon(const Polygon &polyCopy) { vertices = polyCopy.vertices; } //Default Constructor Polygon::Polygon(){} istream & operator >> (istream &inStream, Polygon &vertStr) { inStream >> ws; inStream >> vertStr; return inStream; } any help greatly appreciated, sorry to be so vague, a lecturer has just kind of given us a brief example of stream insertion then left us on our own thanks. oh i realise there are probably many other problems that need fixing

  Read the article

• How to get function name against function address by reading co-classs'es vtable?

  - by Usman

  Hello, I need to call the co-class function by reading its address from vtable of COM exposed interface methods. I need some generic way to read addresses. Now I need to call the function, which would have specific address(NOT KNOWN) arguments(parameters) which I have collected from TLB, and name as well. How that address corresponds to that function name to which I am going to call. For this I need to traverse vtable which is holding functional addresses, LASTLY need to correspond function address with NAME of that function. This is I dont know. How? More over one function with the same name may appear in vtable(Overloading case). In that case we need to distinguish function names w.r.t their addresses. How to tackle ? Regards Usman

  Read the article

• C++ streams operator << and manipulators / formatters

  - by Ayman

  First, most of my recent work was Java. So even though I "know" C++, I do not want to write Java in C++. And C++ templates are one thing I will really miss when going back to Java. Now that this out of the way, if I want to do create a new stream formatter, say pic, that will have a single std::string parameter in it's constructor. I would like the user to be able to write something like: cout << pic("Date is 20../../..") << "100317" << endl; The output should be Date is 2010/03/17 How do I write the pic class? when the compiler sees the cout what are the underlying steps the compiler does?

  Read the article

• Can I have conditional construction of classes when using IoC.Resolve ?

  - by Corpsekicker

  I have a service class which has overloaded constructors. One constructor has 5 parameters and the other has 4. Before I call, var service = IoC.Resolve<IService>(); I want to do a test and based on the result of this test, resolve service using a specific constructor. In other words, bool testPassed = CheckCertainConditions(); if (testPassed) { //Resolve service using 5 paramater constructor } else { //Resolve service using 4 parameter constructor //If I use 5 parameter constructor under these conditions I will have epic fail. } Is there a way I can specify which one I want to use?

  Read the article

• Java operator overload

  - by rengolin

  Coming from C++ to Java, the obvious unanswered question is why not operator overload. On the web some go about: "it's clearly obfuscated and complicate maintenance" but no one really elaborates that further (I completely disagree, actually). Other people pointed out that some objects do have an overload (like String operator +) but that is not extended to other objects nor is extensible to the programmer's decision. I've heard that they're considering extending the favour to BigInt and similar, but why not open that for our decisions? How exactly if complicates maintenance and where on earth does this obfuscate code? Isn't : Complex a, b, c; a = b + c; much simpler than: Complex a, b, c; a.equals( b.add(c) ); ??? Or is it just habit?

  Read the article

• Shortcut "or-assignment" (|=) operator in Java

  - by Dr. Monkey

  I have a long set of comparisons to do in Java, and I'd like to know if one or more of them come out as true. The string of comparisons was long and difficult to read, so I broke it up for readability, and automatically went to use a shortcut operator |= rather than negativeValue = negativeValue || boolean. boolean negativeValue = false; negativeValue |= (defaultStock < 0); negativeValue |= (defaultWholesale < 0); negativeValue |= (defaultRetail < 0); negativeValue |= (defaultDelivery < 0); I expect negativeValue to be true if any of the default<something> values are negative. Is this valid? Will it do what I expect? I couldn't see it mentioned on Sun's site or stackoverflow, but Eclipse doesn't seem to have a problem with it and the code compiles and runs.

  Read the article

• Visitor and templated virtual methods

  - by Thomas Matthews

  In a typical implementation of the Visitor pattern, the class must account for all variations (descendants) of the base class. There are many instances where the same method content in the visitor is applied to the different methods. A templated virtual method would be ideal in this case, but for now, this is not allowed. So, can templated methods be used to resolve virtual methods of the parent class? Given (the foundation): struct Visitor_Base; // Forward declaration. struct Base { virtual accept_visitor(Visitor_Base& visitor) = 0; }; // More forward declarations struct Base_Int; struct Base_Long; struct Base_Short; struct Base_UInt; struct Base_ULong; struct Base_UShort; struct Visitor_Base { virtual void operator()(Base_Int& b) = 0; virtual void operator()(Base_Long& b) = 0; virtual void operator()(Base_Short& b) = 0; virtual void operator()(Base_UInt& b) = 0; virtual void operator()(Base_ULong& b) = 0; virtual void operator()(Base_UShort& b) = 0; }; struct Base_Int : public Base { void accept_visitor(Visitor_Base& visitor) { visitor(*this); } }; struct Base_Long : public Base { void accept_visitor(Visitor_Base& visitor) { visitor(*this); } }; struct Base_Short : public Base { void accept_visitor(Visitor_Base& visitor) { visitor(*this); } }; struct Base_UInt : public Base { void accept_visitor(Visitor_Base& visitor) { visitor(*this); } }; struct Base_ULong : public Base { void accept_visitor(Visitor_Base& visitor) { visitor(*this); } }; struct Base_UShort : public Base { void accept_visitor(Visitor_Base& visitor) { visitor(*this); } }; Now that the foundation is laid, here is where the kicker comes in (templated methods): struct Visitor_Cout : public Visitor { template <class Receiver> void operator() (Receiver& r) { std::cout << "Visitor_Cout method not implemented.\n"; } }; Intentionally, Visitor_Cout does not contain the keyword virtual in the method declaration. All the other attributes of the method signatures match the parent declaration (or perhaps specification). In the big picture, this design allows developers to implement common visitation functionality that differs only by the type of the target object (the object receiving the visit). The implementation above is my suggestion for alerts when the derived visitor implementation hasn't implement an optional method. Is this legal by the C++ specification? (I don't trust when some says that it works with compiler XXX. This is a question against the general language.)

  Read the article

• can i overload a method with another one that takes the same parameters but has a diferent return ty

  - by David

  For example can i have something like this: public static void SAMENAME (sameparameter n) { some code ; } public static String SAMENAME (sameparameter n) { similar code; return someString ; }

  Read the article

• Overload method (specifically drawRect:) without subclassing.

  - by SooDesuNe

  I'm using a container UIView to house a UIImageView and do some custom drawing. At this point I'd like to do some drawing on top of my subview. So overriding drawRect: in my container UIView will only draw below the subviews. Is there a way to overload drawRect: in my subview without subclassing it? I think method swizzling may be the answer, but I'm hoping not. (NOTE: yes, it would have been smarter to have the UIView be the subview of the UIImageView, but unfortunately I'm committed to my mistake now.)

  Read the article

• how do i call an overloaded action in .net mvc?

  - by Jeff Martin

  I have an overloaded action in my Controller: public ActionResult AssignList(int id) { ... } [AcceptVerbs((HttpVerbs.Get))] public ActionResult AssignList(int id, bool altList) { ... } I'd like to use the same partial view for both lists but it will potentially have a differently filtered list of Images. I am trying to call it from another view using RenderAction: <% Html.RenderAction("AssignList", "Image", new { id = Model.PotholeId, altList = true }); %> However I am getting the following error: The current request for action 'AssignList' on controller type 'ImageController' is ambiguous between the following action methods: System.Web.Mvc.ActionResult AssignList(Int32) on type UsiWeb.Controllers.ImageController System.Web.Mvc.ActionResult AssignList(Int32, Boolean) on type UsiWeb.Controllers.ImageController How can I call the specific overload?

  Read the article

• C# 4: conflicting overloaded methods with optional parameters

  - by Thomas

  I have two overloaded methods, one with an optional parameter. void foo(string a) { } void foo(string a, int b = 0) { } now I call: foo("abc"); interestingly the first overload is called. why not the second overload with optional value set to zero? To be honest, I would have expect the compiler to bring an error, at least a warning to avoid unintentional execution of the wrong method. What's the reason for this behaviour? Why did the C# team define it that way? Thanks for your opinions!

  Read the article

• Implementing __concat__

  - by Casebash

  I tried to implement __concat__, but it didn't work >>> class lHolder(): ... def __init__(self,l): ... self.l=l ... def __concat__(self, l2): ... return self.l+l2 ... def __iter__(self): ... return self.l.__iter__() ... >>> lHolder([1])+[2] Traceback (most recent call last): File "<stdin>", line 1, in <module> TypeError: unsupported operand type(s) for +: 'lHolder' and 'list' How can I fix this?

  Read the article

• How to write a code Newton Raphson code in R involving integration and Bessel function

  - by Ahmed

  I have want to estimate the parameters of the function which involves Bessel function and integration. However, when i tried to run it, i got a message that "Error in f(x, ...) : could not find function "BesselI" ". I don't know to fix it and would appreciate any related proposal. library(Bessel) library(maxLik) library(miscTools) K<-300 f <- function(theta,lambda,u) {exp(-u*theta)*BesselI(2*sqrt(t*u*theta*lambda),1)/u^0.5} F <- function(theta,lambda){integrate(f,0,K,theta=theta,lambda=lambda)$value} tt<-function(theta,lambda){(sqrt(lambda)*exp(-t*lambda)/(2*sqrt(t*theta)))(theta(2*t*lambda-1)*F(theta,lambda)} loglik <- function(param) { theta <- param[1] lambda <- param[2] ll <-sum(log(tt(theta,lambda))) } t<-c(24,220,340,620,550,559,689,543) res <- maxNR(loglik, start=c(0.001,0.0005),print.level=1,tol = 1e-08) summary(res)

  Read the article

• Operator issues with cout

  - by BSchlinker

  I have a simple package class which is overloaded so I can output package data simply with cout << packagename. I also have two data types, name which is a string and shipping cost with a double. protected: string name; string address; double weight; double shippingcost; ostream &operator<<( ostream &output, const Package &package ) { output << "Package Information ---------------"; output << "Recipient: " << package.name << endl; output << "Shipping Cost (including any applicable fees): " << package.shippingcost; The problem is occurring with the 4th line (output << "Recipient:...). I'm receiving the error "no operator "<<" matches these operands". However, line 5 is fine. I'm guessing this has to do with the data type being a string for the package name. Any ideas?

  Read the article

• Python: Can subclasses overload inherited methods?

  - by Rosarch

  I'm making a shopping cart app in Google App Engine. I have many classes that derive from a base handler: class BaseHandler(webapp.RequestHandler): def get(self, CSIN=None): self.body(CSIN) Does this mean that the body() method of every descendant class needs to have the same argument? This is cumbersome. Only one descendant actually uses that argument. And what about when I add new args? Do I need to go through and change every class? class Detail(BaseHandler): def body(self, CSIN): class MainPage(BaseHandler): def body(self, CSIN=None): #@UnusedVariable class Cart(BaseHandler): def body(self, CSIN): #@UnusedVariable

  Read the article

• How to return the output of a recursive function in Clojure

  - by Silanglaya Valerio

  Hi everyone! I'm new to functional languages and clojure, so please bear with me... I'm trying to construct a list of functions, with either random parameters or constants. The function that constructs the list of functions is already working, though it doesn't return the function itself. I verified this using println. Here is the snippet: (def operations (list #(- %1 %2) #(+ %1 %2) #(* %1 %2) #(/ %1 %2))) (def parameters (list \u \v \w \x \y \z)) (def parameterlistcount 6) (def paramcount 2) (def opcount 4) (defn generateFunction "Generates a random function list" ([] (generateFunction 2 4 0.5 0.6 '())) ([pc maxdepth fp pp function] (if (and (> maxdepth 0) (< (rand) fp)) (dotimes [i 2] (println(conj (generateFunction pc (dec maxdepth) fp pp function) {:op (nth operations (rand-int opcount))}))) (if (and (< (rand) pp) (> pc 0)) (do (dec pc) (conj function {:param (nth parameters (rand-int parameterlistcount))})) (conj function {:const (rand-int 100)}))))) Any help will be appreciated, thanks!

  Read the article

• Override number of parameters of pure virtual functions

  - by Jir

  I have implemented the following interface: template <typename T> class Variable { public: Variable (T v) : m_value (v) {} virtual void Callback () = 0; private: T m_value; }; A proper derived class would be defined like this: class Derived : public Variable<int> { public: Derived (int v) : Variable<int> (v) {} void Callback () {} }; However, I would like to derive classes where Callback accepts different parameters (eg: void Callback (int a, int b)). Is there a way to do it?

  Read the article

• operator<< cannot output std::endl -- Fix?

  - by dehmann

  The following code gives an error when it's supposed to output just std::endl: #include <iostream> #include <sstream> struct MyStream { std::ostream* out_; MyStream(std::ostream* out) : out_(out) {} std::ostream& operator<<(const std::string& s) { (*out_) << s; return *out_; } }; template<class OutputStream> struct Foo { OutputStream* out_; Foo(OutputStream* out) : out_(out) {} void test() { (*out_) << "OK" << std::endl; (*out_) << std::endl; // ERROR } }; int main(int argc, char** argv){ MyStream out(&std::cout); Foo<MyStream> foo(&out); foo.test(); return EXIT_SUCCESS; } The error is: stream1.cpp:19: error: no match for 'operator<<' in '*((Foo<MyStream>*)this)->Foo<MyStream>::out_ << std::endl' stream1.cpp:7: note: candidates are: std::ostream& MyStream::operator<<(const std::string&) So it can output a string (see line above the error), but not just the std::endl, presumably because std::endl is not a string, but the operator<< definition asks for a string. Templating the operator<< didn't help: template<class T> std::ostream& operator<<(const T& s) { ... } How can I make the code work? Thanks!

  Read the article

• Custom types as key for a map - C++

  - by Appu

  I am trying to assign a custom type as a key for std::map. Here is the type which I am using as key. struct Foo { Foo(std::string s) : foo_value(s){} bool operator<(const Foo& foo1) { return foo_value < foo1.foo_value; } bool operator>(const Foo& foo1) { return foo_value > foo1.foo_value; } std::string foo_value; }; When used with std::map, I am getting the following error. error C2678: binary '<' : no operator found which takes a left-hand operand of type 'const Foo' (or there is no acceptable conversion) c:\program files\microsoft visual studio 8\vc\include\functional 143 If I change the struct like the below, everything worked. struct Foo { Foo(std::string s) : foo_value(s) {} friend bool operator<(const Foo& foo,const Foo& foo1) { return foo.foo_value < foo1.foo_value; } friend bool operator>(const Foo& foo,const Foo& foo1) { return foo.foo_value > foo1.foo_value; } std::string foo_value; }; Nothing changed except making the operator overloads as friend. I am wondering why my first code is not working? Any thoughts?

  Read the article

• Overload dereference operator

  - by zilgo

  I'm trying to overload the dereference operator, but compiling the following code results in the error 'initializing' : cannot convert from 'X' to 'int': struct X { void f() {} int operator*() const { return 5; } }; int main() { X* x = new X; int t = *x; delete x; return -898; } What am I doing wrong?

  Read the article

• Tabexpansion function Does Not Resolve Variable

  - by chadwickmiller

  I'm attempting to override and implement my own TabExpansion. In the function I want to parse the contents of $psise.CurrentFile.Editor.Text when a certain $lastword criteria is matched. The issue I have is that the variable $psise.CurrentFile.Editor.Text is resolved to the contents of my TabExpansion function rather than whatever text is in a PowerShell ISE tab. Here's simple test function. Open an ISE tab and paste the following tabexpansion function definition: function tabexpansion { $psise.CurrentFile.Editor.Text } Run the script in ISE. Next open another tab in ISE type some text and press the tab key The output will be function tabexpansion { $psise.CurrentFile.Editor.Text } Rather than whatever text was in the second tab. Is there any way to get $psise.CurrentFile.Editor.Text to resolve at runtime when used within a tabexpansion function?

  Read the article

• how to refer to the current struct in an overloaded operator?

  - by genesys

  Hi! I have a struct for which i want to define a relative order by defining < , , <= and = operators. actually in my order there won't be any equality, so if one struct is not smaller than another, it's automatically larger. I defined the first operator like this: struct MyStruct{ ... ... bool operator < (const MyStruct &b) const {return (somefancycomputation);} }; now i'd like to define the other operators based on this operator, such that <= will return the same as < and the other two will simply return the oposite. so for example for the operator i'd like to write something like bool operator > (const MyStruct &b) const {return !(self<b);} but i don't know how to refere to this 'self' since i can refere only to the fields inside the current struct. whole is in C++ hope my question was understandable :) thank you for the help!

  Read the article

• Operator overload for [] operator

  - by viswanathan

  Why would you need to overload the [] operator? I have never come across a practical scenario where this was necessary. Can somebody tell me a practical use case for this.

  Read the article

< Previous Page | 43 44 45 46 47 48 49 50 51 52 53 54  | Next Page >