Question

I’m overloading the ++ prefix operator using a member function. Here’s the prototype:

Test &operator++();

But my doubt comes when I use it for my object like below:

Test t;
++t;

As far I have learned that for any operator overloaded by a member function there should be a object of that same class on left side of that operator. But when I am calling this ++ prefix overloaded operator, I don’t need any object of Test class on the left side.

Why?

Answer 1

As far I have learned that for any operator overloaded by a member function there should be a object of that same class on left side of that operator.

That would hold for any binary operator. Pre- and post-incrementations, as well as the dereference operator (*obj) are unary operators. They have a single argument (either a function parameter or implied “this” parameter, depending on how you overload the operator) and for overloaded operators this only argument must be of a class type.

But when I am calling this ++ prefix overloaded operator, I don’t need any object of Test class on the left side.

Unary operators don’t have a “left” and “right” sides (operands), they only have one operand.

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Remember that in your case:

++t;

means just:

t.operator++();

So – in some twisted thinking – t is indeed on the left side. 🙂