Just as a class can grant private access to a non-member function via friend functions, it can also grant private access to an entire class. This can be beneficial if there is a coupling between two classes. Introducing friend classes…
Just like static members variables, static methods are also a thing. They can be called directly using ::. Calling a static method through the class Since static methods belong to the class they can be called directly. No BatteryMonitorConfig object is created.…
Consider a class with member variables. Each time an instance is made, each object gets a duplicate of the member variables. A member variable can be assigned static. This means all class objects share (reference) the same member. This allows…
Just as you can have structs contain other structs, similarly, you can have classes contain other classes. This is called a nested class. A helper class that belongs to one class Consider a Playlist class. We want a small helper that prints…
The problem Consider this program: This works, but DoorState exists outside the Door class although it’s designed to be used with Door. If only there was a way to embed Door inside the class, thereby making the relationship explicit. Nested types So far we’ve covered…
The problem Consider this class: Both objects call the same member function: setVolume() But this call modifies music: music.setVolume(50); and this call modifies effects: effects.setVolume(20); How does C++ know which object m_volume belongs to? The answer is the hidden this pointer. What this means Inside a non-static member…
Three things to take away: The problem Consider the following: This compiles. Even though it is semantically meaningless. C++ uses implicit conversions and converts true to int, then uses the constructor: RareMacGuffin(int rarityLevel) to create a temporary RareMacGuffin. The result is technically correct but…
#116 – Crash course on the copy constructor communicated how copy elision removed 2 instances of the copy constructor from executing. Modern C++ supports 3 ways to construct classes: copy initialization, direct initialization, and list initialization The apparent copy Consider…
Copying an object Consider a simple Triangle class: This line constructs copy from another Triangle: Triangle copy { original }; That calls the copy constructor. Since we did not define a copy constructor, the compiler generates one for us. The compiler-generated copy constructor performs memberwise…
Consider a simple Coordinate class: This is perfectly valid. But if spawnPoint is only created so it can be passed into print(). This is inefficient. We can do better. We can merge these 2 instruction by using a temporary class object. Creating a temporary class…