object-oriented programming, a modular approach to computer program (software) design. Each module, or object, combines data and procedures (sequences of instructions) that act on the data; in traditional, or procedural, programming the data are separated from the instructions. A group of objects that have properties, operations, and behaviors in common is called a class. By reusing classes developed for previous applications, new applications can be developed faster with improved reliability and consistency of design. The first object-oriented programs, written in the language Simula 67, were used extensively for modeling and simulation, primarily in Europe during the late 1960s and early 1970s. The technique was popularized in the United States during the following decade using the language SmallTalk and achieved its greatest prominence with the development of the object-oriented language C++ during the late 1980s and 1990s.
See P. W. Oman and T. G. Lewis, Milestones in Software Evolution (1990); T. Budd, An Introduction to Object-Oriented Programming (1991); P. Varhol, Object-Oriented Programming: The Software Development Revolution (1993); P. Coad and J. Nicola, OOP, Object-Oriented Programming (1993).