Copy constructor may not be called due to the auto-optimization of compilers. It’s quite compiler specific. See code as follows.
#include <iostream>
using namespace std;
class Point {
public:
Point(int a = 0, int b = 0) : x(a), y(b) {
//note that only in VS 2019, when we want print address, it won't print Ox, while Unix-like does print
cout << "Constructor called --> P(" << x << ',' << y << ")" << "\t with address --> 0x" << this << "\n\n";
}
Point(const Point& A) : x(A.x), y(A.y) {
cout << "Copy constructor called --> P(" << x << ',' << y << ")" << "\t with address --> 0x" << this << "\n\n";
}
// try to umcomment move constructor/assignment
/*Point(Point&& A) noexcept :x{ 0 }, y{ 0 } {
swap(x, A.x); swap(y, A.y);
cout << "Move constructor called --> P(" << x << ',' << y << ")" << "\t with address --> 0x" << this << "\n\n";
}
Point& operator=(Point&& A)noexcept {
if (this == &A) return *this;
swap(x, A.x); swap(y, A.y);
cout << "Move assignment called --> P(" << x << ',' << y << ")" << "\t with address --> 0x" << this << "\n\n";
return *this;
}*/
Point& operator=(const Point& A) {
x = A.x; y = A.y;
cout << "Copy assignment called --> P(" << x << ',' << y << ")" << "\t with address --> 0x" << this << "\n\n";
return *this;
}
~Point() { cout << "Destructor called --> P(" << x << ',' << y << ")" << "\t with address --> 0x" << this << "\n\n"; }
friend Point operator+(const Point A, const Point B) {
// try them respectively and see what's going on
//return Point(A.x + B.x, A.y + B.y);
Point C(A.x + B.x, A.y + B.y);
return C;
}
friend ostream& operator<<(ostream& os, const Point& A) {
os << "(" << A.x << ',' << A.y << ")";
return os;
}
private:
int x, y;
};
int main()
{
Point A(1, 2);
Point B(8, 9);
// try them respectively and see what's going on
Point C;
C = A + B;
//Point C = A + B;
cout << C << "\n\n";
return 0;
}
Also very interesting to note that the order of copy assignment called in main function & that of destructors in which objects constructed by parameters and locals constructed in subroutine operator+, varies in differing systems.
Somehow, this evening I suddenly felt an intense feeling of belonging to sea, to the Nature. It kinda like the voice of my soul in response to the call of the Nature, in a way, I now find the feeling is extremely like the one of Tristan (a role in Legends of the Fall acted by Brad Pitt) that his running wild horse in his mind wants to seek for some inner peace, for he is plagued with guilt over Samuel’s death and feels responsible for driving Alfred away after he returns home.
The feeling, however, didn’t last very long, say about an hour (maybe 40 minutes), but it was amazingly fantastic – I just wanted to go wild, be wild about the sea, the ocean, the mountain, the cloud, the sky, the sun, everything, everything in the Nature. Then gone, leaving a piece of calm and peace, like the water in the lake, so peaceful.
(By the way, these beautiful images are downloaded from Pixabay, you can find a tremendous number of stunning free images there.)
The work of teaching is simultaneously mental and social. It is also physical, emotional, practical, behavioral, political, experimental, historical, cultural, spiritual and personal. To sum up, teaching is very complex.
When language teaching in particular is in focus, the challenge is even greater, shaped by teacher’s view of the nature of language, of language teaching, and learning in general.
So to speak, the teacher is practitioner and theory builder.
This morning, a crazy idea came across my mind somehow, and I found it could be a great opportunity & treasure if we can seize it properly. The idea is we can build a blog network of our high school class, and each one of us is capable of writing, editing, & managing his or her own blogs in convenience, but meanwhile be able to view other classmates’ blogs, and leave a significant or funny comment. Surprisingly, I found WordPress is good one for this. Besides, it also provides a shared library (the Media lib), which means you’re allowed to use the uploaded images, audios, & videos by other authors.
(Following content is added on Apr 4, 2020)
Well, the shared library (the Media) may be undesirable for some authors who want their posts & the media published to be only seen by themselves or people they would like to let see. This is reasonable, human needs privacy. It is natural to think is there a technique that can allow authors to encrypt their posts if they want keep their content secure. After Googling it, I find it is possible.
Doing…
(the wee hours of Apr 5, 2020 )
Amazingly, WordPress provides a substantial number of plugins, which virtually renders every idea you think possible. With those plugins, you are capable of encrypting your post with a password and you can give it to anyone you want for accessing your secret content; each author can also have their own media library, thus further saved their privacy from other authors; co-authors working is also available (like this post, I added some other authors so that they can also edit it), etc. In a word, there are tremendous of awesome stuff we can do in WordPress with those incredible plugins.
So, if privacy is no longer a issue, I really wish my dear classmates can do join our legendary Class 1 WordPress Blog Network. Writing can be really funny, especially when you get lots of companies who by any chance are your old old friends (good buddies). By that time, noting down & sharing the wonderful moment can be a really a delightful thing (Your amazing friends may leave you a significant or funny comment. You will be so gonna love it!).
Lastly, I wanna say that writing can be really an agreeable & fruitful thing, for the writing duration, you are doing an incredible thing – thinking, one thing that distinguishes people from animals. (Oh, no! Some might say, animals DO think too. Yes, precisely. But we humans are thinking logically, emotionally, & intuitively.) And I genuinely wish each guy of our awesome class 1 can get involved into this activity. You guys even went through the hard-ass college entrance examination, so I do believe all of you guys can nail it!
There is a pleasure in the pathless woods… There is a rapture on the lonely shore… There is a society where none intrudes… By the deep sea and music in its roar… I love not mean the less, but Nature more… From these our interviews, in which I steal… From all I maybe, or have been before. To mingle with the Universe and feel… What I can ne’er express, yet cannot all conceal.
