結局C++とRustってどっちが良いの？ 5traits

$ cat test.cpp
#include <iostream>
#include <cstdint>
using namespace std;
struct Foo {
uint64_t a;
uint64_t b;
static Foo new_ (uint64_t a) {
Foo foo; foo.a = a;
cout << "foo: " << &foo << '\n';
return foo;
}
};
int main () {
auto fff {Foo::new_ (123)};
cout << "foo: " << &fff << '\n';
return 0;
}
$ g++ -O0 -std=c++20 -o test test.cpp
$ ./test
foo: 0x7fff0bbf3540
foo: 0x7fff0bbf3560
$ g++ -O3 -std=c++20 -o test test.cpp
$ ./test
foo: 0x7ffed05f53a0
foo: 0x7ffed05f53a0