why the << operator is friend

The << operator in C++ is often overloaded for output streams, such as std::cout, to enable the insertion of data into the stream. It is commonly used for printing or displaying data on the console or other output devices.

The << operator is typically implemented as a friend function rather than a member function of the stream class. This allows the operator to access the private members of the stream class, such as the internal buffer, without needing to be a member of the class itself. By making the << operator a friend function, it can be defined outside the class definition and still have access to the private members of the stream class.

Here is a step-by-step explanation of why the << operator is often declared as a friend function:

  1. The << operator is declared as a friend function inside the stream class. This allows the operator to access the private members of the stream class.

  2. When the << operator is used with an output stream object, such as std::cout, the operator function is called.

  3. The operator function takes two arguments: the output stream object and the data to be inserted into the stream.

  4. Inside the operator function, the data is inserted into the stream by accessing the internal buffer of the stream object.

  5. The operator function returns a reference to the output stream object, allowing multiple << operators to be chained together.

By declaring the << operator as a friend function, it allows the operator to have access to the private members of the stream class, which is necessary for inserting data into the stream.

[5]