Question: I can operate class+class (for example I can do date+date), but can anyone explain how can I do class+class+class please? C++ does not let me define an operator with 2 parameters.

Answer: 
By making them friends of the class, you would make sure they are binary operators, and define them separately, like so:

```
class someclass
{
     int a;
public:
     someclass();
     ...
     friend someclass operator+(const someclass & lhs, const someclass & rhs);
};

someclass operator+(const someclass &lhs, const someclass &rhs)
{
     someclass a = lhs;
     a.a = a.a + rhs.a;
     return a;
}

```

you will, of course need to define a copy constructor (someclass(const someclass & old);) and the other functions of the class, but this method has always worked for me, and it was how I was taught in college.
You are allowed to use arithmetic operators with two parameters. For example:

```
//References are used here as arguments.
Cents operator+(const Cents &c1, const Cents &c2)
{
    // use the Cents constructor and operator+(int, int)
    return Cents(c1.m_nCents + c2.m_nCents);
}

```

(Source: <http://www.learncpp.com/cpp-tutorial/92-overloading-the-arithmetic-operators/>)

Note: you need to declare the operator "function" as *friend* in class definition if you need to use private members of your class in it.

If you then return a class type same with those given as arguments (objects or references of them as here), you can do class + class + class..., assuming that each operator+ call is between 2 arguments, and the result is added to the third one invoking again the operator+ "function" etc.