/* 編譯指令：g++ test.cpp -fno-elide-constructors
/* 執行結果：
 james732@james:~$ ./a.out
 default constructor
 copy constructor
 copy constructor
 ---------------
 default constructor
 copy constructor
 copy assignment
 default constructor
 copy constructor
 */

#include <iostream>
using namespace std;

class Foo {
public:
    Foo() {
        cout << "default constructor" << endl;
    }
    Foo( const Foo & rh ) {
        cout << "copy constructor" << endl;
    }
    Foo operator=( const Foo & rh ) {
        cout << "copy assignment" << endl;
        Foo f;
        return f;
    }
};

Foo do_something ( ) {
    Foo f1;
    return f1;
}

int main()
{
    Foo f3 = do_something( );
    cout << "---------------" << endl;
    f3 = do_something( );  /* 這行才會引發 assignment */
}