Program construction consists of a sequence of refinement steps.

Niklaus Emil Wirth (born February 15 1934) is a Swiss computer scientist best known for designing several programming languages including Pascal and for pioneering several classic topics in software engineering. From 1963 to 1967 he served as assistant professor of Computer Science at Stanford University and again at the University of Zurich. In 1984 he won the Turing Award for developing a sequence of innovative computer languages.

Niklaus Emil Wirth (born February 15 1934) is a Swiss computer scientist best known for designing several programming languages including Pascal and for pioneering several classic topics in software engineering. In 1984 he won the Turing Award for developing a sequence of innovative computer languages.