Differentiate between object oriented and function oriented design .
Function-oriented design relies on recognizing functions which transform their inputs to make outputs. In most systems, functions share some overall system state.
The functional design process includes identifying data transformations in the system, decomposing functions into a hierarchy of sub-functions, defining the operation and interface of every system entity and documenting the flow of control in the system.
Data-flow diagrams are a means of documenting end-to-end data flow by a system. They do not contain control information. Structure charts are a way of showing the hierarchical organization of a system. Control may be documented using a program description language (PDL).
Data-flow diagrams can be executed directly as a set of cooperating sequential processes. Every transform in the data-flow diagram is executed as a separate process. Alternatively, they can be realized as a number of process in a sequential program.