Consider the following program that makes use of a virtual function: #include <iostream> class Base { public: virtual void print() const { std::cout << “Base”; } }; class Derived : public Base { public: void print() const override { std::cout << “Derived”; } }; int main() { Derived d{}; Base& …
Way back in lesson , we examined the concept of casting, and the use of static_cast to convert variables from one type to another. In this lesson, we’ll continue by examining another type of cast: dynamic_cast. The need for dynamic_cast When dealing with polymorphism, you’ll often encounter cases where you …
Let’s go back to an example we looked at previously: #include <iostream> #include <string_view> class Base { protected: int m_value{}; public: Base(int value) : m_value{ value } { } virtual ~Base() = default; virtual std::string_view getName() const { return “Base”; } int getValue() const { return m_value; } }; class …
You’ve probably seen this program in a lot of textbooks and tutorials: #include <iostream> using namespace std; int main() { cout << “Hello world!\n”; return 0; } If you see this, run. Your textbook or tutorial are probably out of date. In this lesson, we’ll explore why. Tip Some IDEs …
Let’s say you are driving to a friend’s house for the first time, and the address given to you is 245 Front Street in Mill City. Upon reaching Mill City, you take out your map, only to discover that Mill City actually has two different Front Streets across town from …
To address some common challenges with inheritance, C++ has two inheritance-related identifiers: override and final. Note that these identifiers are not keywords — they are normal words that have special meaning only when used in certain contexts. The C++ standard calls them “identifiers with special meaning”, but they are often …
Inheritance allows us to model an is-a relationship between two objects. The object being inherited from is called the parent class, base class, or superclass. The object doing the inheriting is called the child class, derived class, or subclass. When a derived class inherits from a base class, the derived …
In this chapter, we learned about some different kinds of relationships between two objects. Summary The process of building complex objects from simpler ones is called object composition. There are two types of object composition: composition, and aggregation. Composition exists when a member of a class has a part-of relationship …
So, you’ve written a program, it compiles, and it even appears to work! What now? Well, it depends. If you’ve written your program to be run once and discarded, then you’re done. In this case, it may not matter that your program doesn’t work for every case — if it …
So far, we’ve explored 3 types of relationships: composition, aggregation, and association. We’ve saved the simplest one for last: dependencies. In casual conversation, we use the term dependency to indicate that an object is reliant upon another object for a given task. For example, if you break your foot, you …
