1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
| class MyClass {
public:
// Default constructor
MyClass() {
std::cout << "Default constructor called\n";
}
// Copy constructor
MyClass(const MyClass&) {
std::cout << "Copy constructor called\n";
}
~MyClass(){
std::cout << "MyClass Dtor called\n";
}
};
void funcByConstRef(const MyClass &obj) {
std::cout << "Inside funcByConstRef\n";
}
class B{
public:
B(){std::cout << "B ctor\n"; }
void foo(){ std::cout << "B foo\n"; }
~B(){ std::cout << "B dtor\n"; }
const MyClass& m {};
};
int main() {
// Passing by const reference:
funcByConstRef(MyClass()); // No copy is made, copy constructor is NOT called. The temporary object's lifetime is simply extended.
std::cout << "==============================\n";
B b; // can see 'MyClass Dtor called' here. So the const lvalue reference is no longer valid!!
b.foo();
return 0;
}
|
