Shallow copy vs deep copy C++

Shallow copying

Because C++ does not know much about your class, the default copy constructor and default assignment operators it provides use a copying method known as a memberwise copy [also known as a shallow copy]. This means that C++ copies each member of the class individually [using the assignment operator for overloaded operator=, and direct initialization for the copy constructor]. When classes are simple [e.g. do not contain any dynamically allocated memory], this works very well.

For example, let’s take a look at our Fraction class:

#include 
#include 
 
class Fraction
{
private:
    int m_numerator { 0 };
    int m_denominator { 1 };
 
public:
    // Default constructor
    Fraction[int numerator = 0, int denominator = 1]
        : m_numerator{ numerator }
        , m_denominator{ denominator }
    {
        assert[denominator != 0];
    }
 
    friend std::ostream& operator