I'm a little confused as to the mechanics of the copy constructor. Correct me if I'm wrong: If a method takes a reference to an object as a parameter, and the class defines a copy construtor, then the class uses the constructor to create a copy of itself and that gets passed to the function instead of a reference to the original object...
I have a stream of data which is contained in a System::Collections::Queue. My data source can output the same data to multiple streams but to do so, needs to duplicate the data for each one. I currently do the following: void DataGatherer::AddMyDataToQueues(MyData^ data) { // Send duplicates to all queues for( int i = 0; i < m_...
I'm writing a math library as a practical exercise. I've run into some problems when overloading the = operator. When I debuged it, I noticed that the call to vertex1 = vertex2 calls the copy constructor instead. In the header file I have: //constructors vector3(); vector3( vector3 &v ); vector3(float ix, float iy, float iz); //opera...
Hi Here is my class that implements copy constructor public class TestCopyConst { public int i=0; public TestCopyConst(TestCopyConst tcc) { this.i=tcc.i; } } i tried to create a instance for the above class in my main method TestCopyConst testCopyConst = new TestCopyConst(?); I am not sure what i should pass...
For this program #include <iostream> using std::cout; struct C { C() { cout << "Default C called!\n"; } C(const C &rhs) { cout << "CC called!\n"; } }; const C f() { cout << "Entered f()!\n"; return C(); } int main() { C a = f(); C b = a; return 0; } the output I get is: Entered f()! Default C called! ...
Hello all. My first post here so be please be kind :) I searched SO before posting but I couldn't find an answer (it's possible that my search wasn't the best though) I'm starting to learn C++ and as an exercise decide to implement a simple LinkedList class (Below there is part of the code). I have a question regarding the way the cop...
This is just a quick question to understand correctly what happens when you create a class with a constructor like this: class A { public: A() {} }; I know that no default constructor is generated since it is already defined but are copy and assignment constructors generated by the compiler or in other words do i need to declar...
I would like to ask you how to write a copy constructor (and operator = ) for the following classes. Class Node stores coordinates x,y of each node and pointer to another node. class Node { private: double x, y; Node *n; public: Node (double xx, double yy, Node *nn) : x(xx), y(yy), n(nn) {} void setNode (Node *nn) : n(nn) {} ... }; ...
From previous post, I learnt that for there are two ways, at least, to declare an array without default constructors. Like this class Foo{ public: Foo(int i) {} }; Foo f[5] = {1,2,3,4,5}; Foo f[5] = {Foo(1), Foo(2), Foo(3), Foo(4), Foo(5)}; I also learnt that the first one will construct the object using the parameter...
Hi, I wonder if there is something wrong with the copy constructor function below? class A { private: int m; public: A(A a){m=a.m} } Thanks and regards! ...
Why are copy constructors unnecessary for immutable objects? Please explain this for me. ...
clone method vs copy constructor in java. which one is correct solution. where to use each case? ...
Here is an extract from item 56 of the book "C++ Gotchas": It's not uncommon to see a simple initialization of a Y object written any of three different ways, as if they were equivalent. Y a( 1066 ); Y b = Y(1066); Y c = 1066; In point of fact, all three of these initializations will probably result in the same obje...
I have two copy constructors Foo(Foo &obj){ } Foo(Foo *obj){ } When will the second copy constructor will get called? ...
Hello What is "minimal framework" (necessary methods) of object, which I will store in STL <vector>? For my assumptions: #include <vector> #include <cstring> using namespace std; class Doit { private: char *a; public: Doit(){a=(char*)malloc(10);} ~Doit(){free(a);} }; int main(){ vector<Doit> v(10);...
std::string x(x); This crashes very badly on my compiler. Does this mean I should test for this != &that in my own copy constructors, or can I assume that no client will ever be so stupid? ...
I'm extracting files from zip and rar archives into raw buffers. I created the following to wrap minizip and unrarlib: Archive.hpp - Used to access everything. If I could make all the functions in the other classes inaccessible from the outside, I would. (Actually, I suppose I could friend all the other classes in Archive and use privat...
class member { public: member() { cout<<"Calling member constr"<<'\n'; } member(const member&) { cout<<"Calling member copy constr"<<'\n'; } }; class fred { public: fred() { cout<<"calling fred constr"<<'\n'; } fred(const fred &) { cout<<"Calling fred copy constr...
Are there some drawbacks of such implementation of copy-constructor? Foo::Foo(const Foo& i_foo) { *this = i_foo; } As I remember, it was recommend in some book to call copy constructor from assignment operator and use well-known swap trick, but I don't remember, why... ...
Stepping through my program in gdb, line 108 returns right back to the calling function, and doesn't call the copy constructor in class A, like (I thought) it should: template <class S> class A{ //etc... A( const A & old ){ //do stuff... } //etc... }; template <class T> class B{ //etc... A<T> ReturnsAnA(...