The confusion is possibly almost appropriate, given so much of his work was on creating systems which avoid confusion through using proper synchronized communication channels. The null pointer stuff is famous, but it's occam and the Communicating Sequential Processes work that were brilliant. Maybe it's also brilliantly wrong, as I think Actor model people could argue, but it is brilliant.

My favourite quote of his is “There are two ways of constructing a piece of software: One is to make it so simple that there are obviously no errors, and the other is to make it so complicated that there are no obvious errors.”

While we hope it's not true, if it is a very deserved RIP.

Most discussions here focus on quicksort and the null reference mistake, but his work on communicating sequential processes (CSP) laid the theoretical foundation for modern concurrent and distributed system design. Hoare logic also created the baseline for all formal verification work that's only now starting to see widespread production use, decades after he first published it. Few computer scientists have contributed work that impacts day-to-day coding, algorithm design, and core system architecture at this fundamental a level.

Damn.

Tony Hoare was on my bucket list of people I wanted to meet before I or they die. My grad school advisor always talked of him extremely highly, and while I cannot seem to confirm it, I believe Hoare might have been his PhD advisor.

It's hard to overstate how important Hoare was. CSP and Hoare Logic and UTP are all basically entire fields in their own right. It makes me sad he's gone.

Sad that his (and many others') dream of widespread formal verification of software never came true. He made really fundamental contributions to computer science but will probably be mostly known for quicksort and the quote about his "billion dollar mistake", not his decades-long program to make formal methods more tractable.

Makes me think of an anecdote where Dijkstra said that he feared he would only be remembered for his shortest path algorithm.

I first came across Tony Hoare about 24 years ago while learning C from The C Programming Language by Kernighan and Richie. I knew him only as C. A. R. Hoare for a long time. When I got on the Internet, it took me a while to realise that when people said Tony Hoare, it was the same person I knew as C. A. R. Hoare. Quoting the relevant text from the book:

> Another good example of recursion is quicksort, a sorting algorithm developed by C.A.R. Hoare in 1962. Given an array, one element is chosen and the others partitioned in two subsets - those less than the partition element and those greater than or equal to it. The same process is then applied recursively to the two subsets. When a subset has fewer than two elements, it doesn't need any sorting; this stops the recursion.

> Our version of quicksort is not the fastest possible, but it's one of the simplest. We use the middle element of each subarray for partitioning. [...]

It was one of the first few 'serious' algorithms I learnt to implement on my own. More generally, the book had a profound impact on my life. It made me fall in love with computer programming and ultimately choose it as my career. Thanks to K&R, Tony Hoare and the many other giants on whose shoulders I stand.

Pardon if I’m dumb/missed something: Is Tony Hoare dead? I see no news anywhere.

  > Jonathan Bowen informed me of Tony Hoare's death on Thursday, March 5th. (translated from French)

One of Billy Crystal's later standup bits was talking about how his parents have hit an age where their favorite game with their friends is called, "Guess Who Died". I've been thinking about that bit an awful lot the last couple of years.

This post appears to have been hidden from the front page of HN?

I saw a casual lecture given by Tony Hoare as a teenager. The atmosphere was warm and welcoming, even if I didn't fully understand all of the content. I remember he was very kind and answered my simple questions politely.

Sir Tony Hoare visited Institute for System Programming in Moscow and gave a lecture quarter of the century ago. It was unforgettable experience to see the living legend of your field. He was a senior person then already and today I am going to celebrate his long and wonderful life.

"The null reference was my billion dollar mistake responsible for innumerable errors, vulnerabilities and system crashes" (paraphrasing). I don't know. This design choice exposed the developer to system realities, and modern language approaches are based on decades of attempts to improve on it, and they are not necessarily better. Safer yes, but more weighty.

Can anyone suggest a better approach for a situation like this in the future? What's better than exposing addressing the problem with a light solution?

RIP: https://youtu.be/tAl6wzDTrJA

Wikipedia is reporting him as deceased, but there’s a bit of an editing war going on. No source is cited for his death, and and it’s going back and forth.

Once verified, I definitely think the creator of Quicksort deserves a black bar.

always knew him as C.A.R. Hoare, takes me way back to freshman college years

RIP good sir

Wikipedia seems to say he passed yesterday.

He was a professor at my old alma mater, Queen's University of Belfast. I remember hearing a story about him going to Harvard to give a lecture and, as he was presented, one of their professors referred to himself as the "Hoare of Harvard"

Time for a black band.

@dang is there such a thing as a double black bar? Because we need one for Tony.