What is the condition when it is necessary to use friend function in operator overloading?

In the case of a friend function, the binary operator should have only two argument and unary should have only one argument. All the class member object should be public if operator overloading is implemented. Operators that cannot be overloaded are . . * :: ?:

Can we do operator overloading without friend function?

As long as the function only calls public member functions of the class (or accesses public data members, if any) it does not need to be a friend. Your Vector example is only accessing public members, hence it works. Your Punkt2D is accessing private members, so the operator needs to be a friend.

What is friend function when is friend function is compulsory give an example?

n that case, the functions don’t need to be declared as friends of the class, because they don’t need access to private members. But these functions typically need to access at least one private member, so to gain that access, they need to be declared as friends of the class.

Why is a friend function required?

Use of Friend function in C++ As discussed, we require friend functions whenever we have to access the private or protected members of a class. This is only the case when we do not want to use the objects of that class to access these private or protected members.

Which operator overloading is friend function?

Overload Binary Operator using Friend Function If you define operator function as a friend function then it will accept two arguments. Because friend functions is not a member function so it is not invoked using object of the class.

Which is better friend function or operator overloading?

Friend function using operator overloading offers better flexibility to the class. These functions are not a members of the class and they do not have ‘this’ pointer. When you overload a unary operator you have to pass one argument.

When to declare an overloaded operator in a class?

An overloaded operator friend could be declared in either private or public section of a class. When an operator overloaded function is a friend function, it takes two operands of user-defined data type. When redefining the meaning of an operator by operator overloading friend function, we cannot change its basic meaning.

Can a binary function be overloaded with a friend function?

When you overload a binary operator you have to pass two arguments. Friend function can access private members of a class directly. In the above program, operator – is overloaded using friend function. The operator () function is defined as a Friend function.

When to use compulsory and friend functions in Java?

compulsory is a strong word – you can usually work around. The friend functions are normally used: to define binary operators, such as operator<<, operator==, or operator+ (regardless of whether they need to access private members or not, there are special properties of friend functions at play here that are not related to access).