ece150: add inheritance

docs/ce1/ece150.md

@@ -129,6 +129,12 @@ Arrays are contiguous in memory and default to 0 when initialised. If field init
 
 Because arrays do not check bounds, `array[n+10]` or `array[-5]` will go to the memory address directed without complaint and ruin your day.
 
+| Pros | Cons |
+| --- | --- |
+| Random access is $O(1)$ | $O(n)$ push front |
+| | Fixed size and unused allocated memory |
+| | Concatenation is slow |
+
 ### Local arrays
 
 Local arrays cannot be assigned to nor returned from a function. If an array is marked `const`, its entries cannot be modified.
@@ -592,3 +598,57 @@ If a move occurs and the compiler determines that the original object is no long
 During construction, default initialisation picks the one with the fewest parameters if ambiguous. Parameters passed by value are **copied** by reference via the copy constructor.
 
 Much like statically allocated arrays, dynamically allocated arrays also automatically dereference when accessed by index.
+
+## Linked lists
+
+Dynamic memory allocation for many objects instead of one like arrays is slow.
+
+## Inheritance
+
+All member functions and the destructor must be `virtual` functions if they can be inherited.
+
+```cpp
+class Base {
+  public:
+    Base();
+    virtual ~Base();
+    virtual Base get_base() const;
+    virtual void set_base();
+    virtual void do_base() const;
+```
+
+A class that inherits another should contain `public <Base>` after the name of the class. Overriden functions must have `override` if they should have the same type signature. Otherwise, they reference the base function.
+
+```cpp
+class ExtendedBase: public Base {
+  public:
+    ExtendedBase();
+    Base get_base() const override;
+    void set_base() override;
+    virtual void do_base() override;
+}
+```
+
+Functions can be overriden completely ignoring the function signature by excluding the `override` keyword.
+
+The base class's functions implicitly refer to the current class, so they can be directly called:
+
+```cpp
+void set_base() override {
+  Base::set_base();
+}
+```
+
+### protected
+
+The `protected` access keyword only allows the original class as well as classes that extend the original one to access it.
+
+### Extending exceptions
+
+Exceptions should have two constructors: one for a char array pointer and another a string for the exception message, as well as any additional parameters as desired. The base exception constructor (not `std::exception` because that can't be instantiated`) should be called to do all of the base constructor things.
+
+In addition, a `what()` function with the following signature should always be defined that cannot throw an exception, returning a C-style array.
+
+```cpp
+char const *error::what() const noexcept;
+```