It is meaningless. Copy constructors cannot be overloaded. You either use the compiler-generated default copy constructor or you define your own. Either way, there can only ever be one copy constructor.
The purpose of the copy constructor is to construct a new instance of a class (a new object) from an existing instance of the same class (an existing object). By default, the new object's members will be a bitwise copy (a shallow copy) of the existing object's members. If the class acquires a resource through a member pointer, a user-defined copy constructor must be provided in order to perform a deep copy of that pointer, otherwise you end up with two objects sharing the same resource. This problem does not exist when using smart pointers or resource handles rather than raw pointers.
A copy constructor usually refers to a constructor which takes an object, and returns a copy of that object. I can think of no way to overload the constructor without changing its functionality.
When we are initializing our object with different internal state then we can use the constructor overloading.
yes,because in constructor overloading constructor have same and different parameter list. In method overloading method have same name and different parameter list.
A constructor is just a special form of a method. You can overload constructors in the exact same way as you can overload any other method.
Overloading a function simply means providing the same function name with different argument types. Class constructors are no different. In fact, even if you declare no constructors in a class, there will be two compiler-generated constructor overloads provided for you: a default constructor; and a copy constructor. If you declare any other constructors, the compiler-generated default constructor will no longer be generated. You must declare your own default constructor if you require one. The copy constructor is always generated, however the default implementation only performs a member-wise copy of the class members. If your class contains a pointer to allocated memory you must provide your own copy constructor to perform a deep-copy of those pointers, so each instances "owns" its own copy of the memory.
The first thing to note about constructor overloading is that Java creates a no argument constructor for you if and only if you have not typed a constructor yourself. Every class has a constructor even abstract ones (default no argument constructor). Abstract constructors are always executed. To overload a constructor you can do the following: class Test { String name; Test(String n) { name = n; System.out.println("Constructing Test Object named: " + name); } } In the case above we are overloading the default no argument constructor with a constructor that takes a String parameter. You can write you own no argument constructor as follows: class Test { Test() { System.out.println("Constructing Test Object"); } } To override our own no argument constructor we do this: class Test { Test() { // our no argument constructor System.out.println("Constructing Test Object"); } String name; Test(String n) { // overloading our no argument constructor with this // constructor that take a String parameter name = n; System.out.println("Constructing Test Object named: " + name); } }
No. Java does not support copy constructor
What is the advantage of user-defined copy constructor
Constructor overloading is the feature by which we declare multiple constructors for a single class. Ex: let us say we want to create multiple constructor for a class Test Public class Test { Public Test() { //code } Public Test(int vals) { //code } Public Test(String val) { //code } }
Constructor overloading, just like any function's overloading, is where more than one configuration of parameters exists for the function. Based on the number and type of the parameters, different versions of the function can be resolved by the linker. This is typically used in the constructor as the default constructor (no parameters), the copy constructor (one reference parameter of the same type as the class), and the conversion constructor (any other combination of parameters).
The only similarity is that both constructor and function overloads are distinguished by their signature -- the number and type of their arguments. Functions differ in that they also have a return type, which is also part of the signature, whereas constructors have no return type, not even void.
this in java is a keyword that refers to the current object of the class. It is also used in constructor overloading when you want to invoke one constructor from another within the same class.