Cpp magic methods

C++ defines magic methods that are called when objects are added together, subtracted, multiplied etc.

constructor/destructor

In cpp, constructurs are a functions defined without type, and with the same name as the class.

They can still have specifiers applied to them, however (explicit, ...).

// header
class MyClass
}
    int *ptr;
    public:
        MyClass (int, int);    // constructor
        ~MyClass;              // destructor
};

// source
MyClass::MyClass (int a, int b) {
    cout << "constructed with args" << a << b << endl;
}

MyClass::~MyClass (){
    cout << "class being destroyed" << endl;
    delete ptr;
}

The destructor is run when:

• an object instantiated on the stack goes out of scope
• an object instantiated in memory is deleted with delete <object>.

Overloading Arithmetic

Classes can also be overloaded so that arithmetic can be performed on them.

NOTE:

this isn't clear at all...

class MyDate {
    int seconds_since_unixtime;
}

// returntype   class::operator      argument (in this case, a reference)
MyDate          MyDate::operator+    ( MyDate& var )