Editing Null pointer (section)

== History ==

In 2009, [[Tony Hoare]] stated<ref name=":0">{{cite web
|url=http://www.infoq.com/presentations/Null-References-The-Billion-Dollar-Mistake-Tony-Hoare
|title=Null References: The Billion Dollar Mistake
|publisher=InfoQ.com
|date=2009-08-25
|author=Tony Hoare
|author-link=Tony Hoare
}}</ref><ref>{{cite web
|url=https://qconlondon.com/london-2009/qconlondon.com/london-2009/presentation/Null%2BReferences_%2BThe%2BBillion%2BDollar%2BMistake.html
|title=Presentation: "Null References: The Billion Dollar Mistake"
|publisher=InfoQ.com
|date=2009-08-25
|author=Tony Hoare
|author-link=Tony Hoare
}}</ref>
that he invented the null reference in 1965 as part of the [[ALGOL W]] language. In that 2009 reference Hoare describes his invention as a "billion-dollar mistake":
{{quote|I call it my billion-dollar mistake. It was the invention of the null reference in 1965. At that time, I was designing the first comprehensive type system for references in an object oriented language (ALGOL W). My goal was to ensure that all use of references should be absolutely safe, with checking performed automatically by the compiler. But I couldn't resist the temptation to put in a null reference, simply because it was so easy to implement. This has led to innumerable errors, vulnerabilities, and system crashes, which have probably caused a billion dollars of pain and damage in the last forty years.}}