Authors Scientist Tony Hoare

Tony Hoare

British computer scientist · 1934–2026

Computer scientist known for Quicksort, Hoare logic and influential work on programming languages.

Lifetime
Jan 11, 1934 – Mar 5, 2026 (age 92)
Primary field
Secondary fields

Sir Charles Antony Richard Hoare was born in Colombo, in what was then British Ceylon, but is now Sri Lanka, and studied classics and philosophy at the University of Oxford. During national service he learned Russian, and in 1959, as a visiting student at Moscow State University, he devised Quicksort, which became one of the most widely used sorting algorithms.

Returning to England, he joined the computer manufacturer Elliott Brothers before becoming a professor at Queen’s University Belfast in 1968 and at Oxford in 1977. He developed Hoare logic, a formal system for reasoning about program correctness, and Communicating Sequential Processes, a framework for concurrency.

Hoare received the 1980 ACM Turing Award, the highest honour in computer science, for fundamental contributions to programming languages and was knighted in 2000 for services to education and computer science.

Quotations

Selected works

Scientific paper · 1962
Quicksort

A description of Quicksort, a divide-and-conquer sorting algorithm that partitions data around a pivot element and recursively sorts the resulting sections.

Scientific paper · 1969
An Axiomatic Basis for Computer Programming

An axiomatic method for proving the correctness of computer programs, using logical rules to reason about how statements change program variables.

Inaugural lecture · 1971
Computer Science

Hoare's inaugural lecture at Queen's University Belfast, defining computer science as the art of designing efficient and elegant methods for solving problems by computer.

Essay · 1974
Hints on Programming-Language Design

Practical advice on designing programming languages, arguing that they should prioritise simplicity, reliability and the needs of the programmer over elaborate features.

Lecture · 1981 FEATURED WORK
The Emperor’s Old Clothes

Tony Hoare reflects on his career designing programming languages and software, arguing that reliability depends on simplicity rather than complexity or elaborate features.

Essay · 1983
Programming is an Engineering Profession

An argument that programming should be regarded as a branch of engineering, combining scientific foundations with practical discipline and professional responsibility for reliability.

Inaugural lecture · 1985
The Mathematics of Programming

Hoare's Oxford inaugural lecture, arguing that programming is a mathematical activity and that mathematical methods can ensure programs are correct and reliable.

Monograph · 1985
Communicating Sequential Processes (CSP)

A formal language and theory for describing systems of concurrent processes that interact by communication, providing a rigorous basis for reasoning about concurrency.

Conference paper · 1996
How Did Software Get So Reliable Without Proof?

Hoare examines why software had become highly reliable despite little use of formal proof, and how mathematical theory and engineering practice reinforce one another.

Conference talk · 2009
Null References: The Billion Dollar Mistake

A talk in which Hoare reflects on his 1965 invention of the null reference, calling it a mistake that caused decades of costly software errors.

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