-casting
#include<iostream>
using namespace std;
int main()
{
	int n {55.555};
	cout<<n<<endl;
	double d {n};
	cout<<d<<endl;
}

https://www.learncpp.com/cpp-tutorial/explicit-type-conversion-casting-and-static-cast/

typecast
https://www.learncpp.com/cpp-tutorial/910-overloading-typecasts/

dynamic memory allocation with new and delete

https://www.tutorialspoint.com/cplusplus/cpp_dynamic_memory.htm

when to use new ?

https://stackoverflow.com/questions/655065/when-should-i-use-the-new-keyword-in-c

https://stackoverflow.com/questions/679571/when-to-use-new-and-when-not-to-in-c

for exercise
http://www.cplusplus.com/doc/tutorial/dynamic/

overloading new and delete operators
https://www.geeksforgeeks.org/overloading-new-delete-operator-c/

friend
https://www.geeksforgeeks.org/friend-class-function-cpp/

deep vs shalow copy

introduce copy constructor first

https://tutorialspoint.dev/language/cpp/copy-constructor-in-cpp

https://owlcation.com/stem/Copy-Constructor-shallow-copy-vs-deep-copy

pointers

https://www.geeksforgeeks.org/pointers-c-examples/

function pointers

https://www.geeksforgeeks.org/function-pointer-in-c/

inline functions

https://www.geeksforgeeks.org/inline-functions-cpp/

templates

https://www.geeksforgeeks.org/templates-cpp/

vector

https://www.geeksforgeeks.org/vector-in-cpp-stl/

for_each loop first
https://www.geeksforgeeks.org/for_each-loop-c/

lambda first
https://www.geeksforgeeks.org/lambda-expression-in-c/

threading with callable

https://www.geeksforgeeks.org/multithreading-in-cpp/

The copy constructor for std::shared_ptr creates a second pointer which shared ownership with the first pointer. The pointee will be destroyed when all std::shared_ptr that point to it are destroyed
shared_ptr
https://www.geeksforgeeks.org/auto_ptr-unique_ptr-shared_ptr-weak_ptr-2/

https://badearobert.ro/2018/06/10/make_shared-vs-shared_ptr-constructor/

exception handling

https://www.geeksforgeeks.org/exception-handling-c/

https://www.tutorialspoint.com/cplusplus/cpp_exceptions_handling.htm