This repo documents the transition of the third CS3 lab exercises from Java to C++.
The Course is about programming concepts rather than a specific language.
## Changes
### Worksheet 1
**Element:**
- In Element every mention of Element is replaced with `std::shared_ptr<Element>`.
- Command cmd becomes `std::shared_ptr<Command>`.
- In the constructor `Element(Command cmd)` uses `std::make_shared<Command>(cmd)` to produce a `std::shared_ptr`.
- The destructor `~Element()` may be configured to log destruction of removed Elements.
**CommandList:**
- the `Element root` now is a `shared_ptr<Element>` and is initialized inline with `std::make_shared<Element>(Command("root"))`. This is necessary because a shared pointer is empty upon construction.
- All member functions previously returning `Command`s now return `std::make_shared<Command>`.
This is to allow for returning `nullptr` if something went wrong.
-`getElement()` now returns `std::shared_ptr<Element>`.
-`getPos()` now returns `std::make_shared<Command>`.
- Where appropriate the funtion parameter `int` has been replaced with `unsigned int` to prohibit passing negative values.
- In `add(Command cmd)``std::make_shared<Element>(cmd)` is used to create a new `Element`.
Here is easily visible how std::make_shared<T>() is the C++ equivalent to Java`s `new` operator.
- The `std::bad_alloc`-Exception possibly thrown by `std::make_shared<Element>()` is not catched in `add()`, to not introduce `try{} catch{}` too early.
Thus add() wont return `nullptr`, but crash the program if an error occures.
## Trivia
### smart pointers
- smart pointers point to NULL on construction.
- They can easily be checked for content with
```
if (mySmartPointer)
//has content
else
//is empty
```
- A unique pointer will be destroyed at the end of it's scope.
- A smart pointer will be destroyed when all of it's references are overwritten or the scope of the last reference ends.
