#include <iostream>
using namespace std;
// 복사생성자개념
// 1. 복사생성자의모양
// 2. 사용자가만들지않으면컴파일러가만들어준다.( 멤버복사를수행한다. )
// 3. 복사생성자는언제호출되는가?
// (1) 자신의type으로초기화될때Point p2(p1);
// (2) 함수호출시call by value - const& 로막을수있다.
// (3) 함수가객체를값으로리턴할때.!!
//(3)
class Point
{
public:
Point() { cout << "생성자" << endl; }
Point( int a, int b ) { cout << "생성자" << endl; }
~Point() { cout << "소멸자" << endl; }
Point( const Point& p1 ){ cout << "복사생성자" << endl; }
};
Point foo() //Point p = p1;
{
//Point p1(1, 2);
//cout << "foo" << endl;
//return p1;
cout << "foo" << endl;
// 리턴용도로만사용한다면만들면서리턴해라...
// 리턴용이름없는객체만만들어진다.
// Return Value Optimization..!!( RVO )
return Point(1, 2); // 생성자를사용해서리턴용객체만만든다.
}
void main()
{
cout << "start" << endl;
Point p1;
{
cout << "in block" << endl;
foo();
cout << "out block" << endl;
}
cout << "end" << endl;
}
/*
class Point
{
public:
Point() { cout << "생성자" << endl; }
Point( int a, int b ) { cout << "생성자" << endl; }
~Point() { cout << "소멸자" << endl; }
Point( const Point& p1 ){ cout << "복사생성자" << endl; }
};
void foo( Point p ) //Point p = p1;
{
cout << "foo" << endl;
}
void main()
{
cout << "start" << endl;
Point p1;
{
cout << "in block" << endl;
foo( p1 );
cout << "out block" << endl;
}
cout << "end" << endl;
}
*/
/*
class Point
{
public:
int x;
int y;
Point( int a = 0, int b = 0 ) : x(a), y(b) {}
// 복사생성자: 사용자가만들지않으면컴파일러가만들어준다.
// 기본적으로멤버복사를수행한다.
Point( const &Point p )
{
x = p.x;
y = p.y;
}
};
void main()
{
Point p1;
Point p2(1, 2);
Point p3(p2); // Point( Point );
cout << p3.x << endl;
cout << p3.y << endl;
Point p4 = p3; // Point p4(p3); 복사생성자호출
int a = 0;
int a(0);
}
*/
