State the functional approach of object oriented methods

Moving from a functional approach to an object oriented one needs a translation of functional model elements into object model elements, which is far from being natural or straightforward. Indeed, there is no straight relationship between the two sets, and it is, so, essential to break model elements from one approach in order to get model element fragments which can be used by other. In initial phases of OO design a combined approach was followed, computer scientist tend to use the functional approach in analysis phase and OO approach in that of the design phase. The mixer of a functional approach for analysis and an object-oriented approach for design and implementation need not to exist today, as current object-oriented methods cover the full software lifecycle.