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 …
In the previous two lessons, we’ve looked at two types of object composition, composition and aggregation. Object composition is used to model relationships where a complex object is built from one or more simpler objects (parts). In this lesson, we’ll take a look at a weaker type of relationship between …
Life is full of recurring patterns, relationships, and hierarchies between objects. By exploring and understanding these, we can gain insight into how real-life objects behave, enhancing our understanding of those objects. For example, let’s say one day you’re walking down the street, and you see a bright yellow object attached …
In this chapter, we explored topics related to operator overloading, as well as overloaded typecasts, and topics related to the copy constructor. Summary Operator overloading is a variant of function overloading that lets you overload operators for your classes. When operators are overloaded, the intent of the operators should be …
The assignment operator (operator=) is used to copy values from one object to another already existing object. Assignment vs Copy constructor The purpose of the copy constructor and the assignment operator are almost equivalent — both copy one object to another. However, the copy constructor initializes new objects, whereas the …
By default, C++ will treat any constructor as an implicit conversion operator. Consider the following case: #include <cassert> #include <iostream> class Fraction { private: int m_numerator; int m_denominator; public: // Default constructor Fraction(int numerator = 0, int denominator = 1) : m_numerator(numerator), m_denominator(denominator) { assert(denominator != 0); } // Copy …
Consider the following line of code: int x = 5; This statement uses copy initialization to initialize newly created integer variable x to the value of 5. However, classes are a little more complicated, since they use constructors for initialization. This lesson will examine topics related to copy initialization for …
In the previous lesson, we overloaded operator+ as a friend function: #include <iostream> class Cents { private: int m_cents{}; public: Cents(int cents) : m_cents{ cents } {} // add Cents + Cents using a friend function friend Cents operator+(const Cents& c1, const Cents& c2); int getCents() const { return m_cents; …
Most programs that have a user interface of some kind need to handle user input. In the programs that you have been writing, you have been using std::cin to ask the user to enter text input. Because text input is so free-form (the user can enter anything), it’s very easy …
The concepts of scope, duration, and linkage cause a lot of confusion, so we’re going to take an extra lesson to summarize everything. Some of these things we haven’t covered yet, and they’re here just for completeness / reference later. An identifier’s scope determines where the identifier can be accessed …
