operator-overloading

问题 This question already has answers here : My attempt at value initialization is interpreted as a function declaration, and why doesn't A a(()); solve it? (5 answers) Closed 4 years ago . I have simple class, class Func { public: Func() { cout<<"Constructor"<<endl; } int operator()(int) { cout<<"Operator ()"; return 0; } }; When I create it's object by giving parenthesis, Func f(); , it prints nothing, it should print Constructor . But when I create object without parenthesis it prints

问题 is it possible (in Delphi) to overload operators in classes. I've read some time ago it is possible only for records but I found information that for classes too like in code below: type TMyClass = class class operator Implicit(a: Integer): TMyClass; end; class operator TMyClass.Implicit(a: Integer): TMyClass; begin // ... end; It is (modified) from address: http://docs.embarcadero.com/products/rad_studio/delphiAndcpp2009/HelpUpdate2/EN/html/devcommon/operatoroverloads_xml.html But when I try

问题 I've created simple string class with some extra functions - its mainly for learning purposes. Now i want to overload operator + to allow me add two or more char* to my string. this is what i want to make: tom::string TXT; TXT="abcde" + "1234"; cout << TXT << endl; and output have to be: abcde1234 i want to add more than just const char* later like: .. int NUM=34; TXT="abcd"+NUM+"098"; cout << TXT << endl; and output have to be: abcd34098 ive already done similar thing with operator << TXT <<

问题 I have an implementation of a Queue which requires writing an assignment operator overload. Queue& Queue::operator= (const Queue& rhs){ if(this->head == rhs.head) return *this; Queue * newlist; if(rhs.head == NULL){ // copying over an empty list will clear it. this->clear(); return * newlist; } newlist = new Queue(rhs); cout << "made new queue" << endl; cout << "new list : " << * newlist << endl; return * newlist; } The problem I'm running into is that when I leave this function, the contents

问题 One of my friends is trying to overload an equality operator for comparing colours in Allegro, however it does not work,He gets the error "no match for operator==" This is overloaded outside the Color class/struct, the overloaded operator function is shown below: typedef ALLEGRO_COLOR Color; bool operator==(const Color& rhs) const { if(_col.a==rhs.a && _col.b==rhs.b && _col.g==rhs.g && _col.r==rhs.r) return true; else return false; } . . . //Data member Color _col Im thinking this does not

问题 Hi i want to do the following. I simply want to overload the [] method in order to access the instance variables... I know, it doesn't make great sense at all, but i want to do this for some strange reason :P It will be something like this... class Wata attr_accessor :nombre, :edad def initialize(n,e) @nombre = n @edad = e end def [](iv) self.iv end end juan = Wata.new('juan',123) puts juan['nombre'] But this throw the following error: overload.rb:11:in `[]': undefined method 'iv' for #

问题 I'm having a problem with class operators in TDateTime. type TDateTime = class(TObject) public class operator Add(a: TDateTime; b: TTimeSpan): TDateTime; class operator Subtract(a: TDateTime; b: TTimeSpan): TDateTime; end; implementation class operator TDateTime.Add(a: TDateTime; b: TTimeSpan): TDateTime; begin result := TDateTime.Create(a.Ticks + b.Ticks); end; class operator TDateTime.Subtract(a: TDateTime; b: TTimeSpan): TDateTime; begin result := TDateTime.Create(a.Ticks - b.Ticks); end;

问题 I get a weird effect when trying to overload the + operator and using the Matrix package with sparse matrices. I first define a very simple class that does not use the Matrix package but has a + operator. I then sum two sparse matrices. The first M+M addition delivers the expected result but the second throws an error. Here is a very simple code that generates the error: require(Matrix) setClass("TestM",representation(M='numeric')) setMethod("initialize", "TestM", function(.Object,x) {

问题 I'm working through an assignment in which I must overload the insertion operator to take a Node object. I've created the operator overload function outside the class definition, but inside the node.h file. Everything compiles fine, but the overloaded operator is not called, instead I get simple the address of the object. I'm prohibited from modifying the calling code, so any changes must be to the operator overload. My code as it stands right now: /** OPERATOR << ****************************

问题 I'm new to C++ and trying to figure out the differences between pointer and reference. I've just read this short summary. In the article, the author mentioned that day *operator++ (day *d); won't compile (note: day is an enum type) and argued that the parameter for this overloaded operator function must be type T, T&, or T const&, where T is a class or enum type. I assume that pointer is a built-in type rather than a class or enum so it can't be used to overload operators and that operator