Tony Hoare (born 1934) is a British computer scientist who made fundamental contributions to algorithms, programming languages, and formal methods. His Quicksort algorithm and CSP concurrency model remain widely influential today.
Quicksort (1959)
While working in Moscow on machine translation, Hoare invented Quicksort to sort words for a Russian-English dictionary. The algorithm’s elegant divide-and-conquer approach made it one of the most efficient general-purpose sorting methods.
Hoare Logic
In 1969, Hoare published “An Axiomatic Basis for Computer Programming,” introducing Hoare logic—a formal system for reasoning about program correctness using preconditions and postconditions. This work founded the field of formal verification.
Communicating Sequential Processes
In 1978, Hoare introduced CSP, a formal language for concurrent processes communicating through channels. CSP directly influenced the design of Go’s goroutines and channels, as well as Occam and other concurrent languages.
The Billion-Dollar Mistake
Hoare famously called his invention of null references his “billion-dollar mistake,” acknowledging the countless bugs and crashes caused by null pointer exceptions throughout computing history.
Recognition
Hoare received the Turing Award in 1980 for his contributions to programming languages. He has worked at Oxford University, Microsoft Research Cambridge, and continues to influence formal methods research.