The University of Iowa The College of Liberal Arts and Sciences Department of Computer Science
Lecture/Lab #13
(Run-time) polymorphism, destructors
Is the following a valid C++ program?
struct car { struct engine { engine( car& c ) : car_( c ) {} car& car_; }; engine& open_hood(); void swap_engine( engine& ); private: engine engine_{ *this }; }; engine& car::open_hood() { return engine_; } void car::swap_engine( engine& ) { // ... }
Fix all compilation errors while keeping the class member definitions outside of the class
https://repl.it/@agurtovoy/lab13-exercise1
Open the exercise template
Write your code, press Run to test
When you're done, grab your Repl's link and send it as a direct message to me (agurtovoy)
Click on the corresponding option in the "Lab13 exercises" poll in #general
https://repl.it/@agurtovoy/lab12-polymorphism
struct car { car( std::string const& make, std::string const& model, int year ); void print( std::ostream& ) const; }; struct truck : car { // truck is-a car truck( std::string const& make, std::string const& model, int year, double capacity ); void print( std::ostream& ) const; }; std::ostream& operator<<( std::ostream& out, car const& c ) { c.print( out ); return out; }
Complete the class hierarchy with run-time behavior to match the corresponding test cases
https://repl.it/@agurtovoy/lab13-exercise2
https://repl.it/@agurtovoy/lab13-destructors
struct car { car() { std::cout << "car constructed" << std::endl; } ~car() { std::cout << "car destructed" << std::endl; } }; int main() { car c; }
A special member function that is called right before the object is destroyed (e.g. when the object goes out of scope)
The primary purpose is to free the resources that the object may have acquired during its lifetime
By Aleksey Gurtovoy
