Implicit class member functions in C ++
Implicit member functions of a class in C ++: According to the wiki: http://en.wikipedia.org/wiki/Special_member_functions
Default constructor (unless any other constructor is explicitly declared)
Copy constructor if no move constructor or redirect operator is explicitly declared. If a destructor is declared, then copy constructor generation is deprecated.
Move constructor if no copy constructor, assignment operator, or destructor is explicitly declared.
A copy assignment operator , unless a move constructor or move assignment operator is explicitly declared. If a destructor is declared, generating the copy assignment statement is deprecated.
Move assignment operator unless a copy constructor, copy assignment operator, or destructor is explicitly declared.
Destructor
As stated below:
http://archives.cs.iastate.edu/documents/disk0/00/00/02/43/00000243-02/lcpp_136.html
A default constructor (that is, one with no parameters (section 12.1 [Ellis-Stroustrup90]) if no constructor (with any number of arguments) for the class has been declared.
Copy constructor (Section 12.1 [Ellis-Stroustrup90]) if no copy constructor has been declared.
Destructor (Section 12.4 [Ellis-Stroustrup90]) if no destructor has been declared.
An assignment operator (sections 5.17 and 12.8 of [Ellis-Stroustrup90]), if no assignment operator has been declared.
As stated below:
http://www.picksourcecode.com/ps/ct/16515.php
default constructor
copy constructor
assignment operator
default destructor
address operator
Can anyone provide code examples for: Move Constructor, Copy Assignment Operator, Move Assignment Operator, Assign Operator, Address Operator where they are used as implicit member functions and are not explicitly defined.
thank
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#include <iostream>
/* Empty struct. No function explicitly defined. */
struct Elem
{ };
/* Factory method that returns an rvalue of type Elem. */
Elem make_elem()
{ return Elem(); }
int main() {
/* Use implicit move constructor (the move may be elided
by the compiler, but the compiler won't compile this if
you explicitly delete the move constructor): */
Elem e1 = make_elem();
/* Use copy assignment: */
Elem e2;
e2 = e1;
/* Use move assignment: */
e2 = make_elem();
/* Use address operator: */
std::cout << "e2 is located at " << &e2 << std::endl;
return 0;
}
The above example uses an empty class. You can fill it with data members that have real move semantics (i.e. members where move is really different from copy), for example. a std::vector
, and you get move semantics automatically without defining move constructors or move assignment operators specifically for your class.
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