Constructors, used to create instances of an object, may also be overloaded in some object-oriented programming languages. Because in many languages the constructor's name is predetermined by the name of the class, it would seem that there can be only one constructor. Whenever multiple constructors are needed, they are to be implemented as overloaded functions. In C++, default constructors take no parameters, instantiating the object members with their appropriate default values. For example, a default constructor for a restaurant bill object written in C++ might set the tip to 15%: