9 Feb
2017
9 Feb
'17
1:03 a.m.
I'm fairly certain it was originally in BCPL.
You could just drop a note to Bjarne Stroustrup and ask. :-)
On page 44 of _The Design and Evolution of C++_ (Addison-Wesley, 1994), Stroustrup says:
“However, only C, Simula, Algol68, an in one case BCPL left noticeable traces in C++ as
released in 1985. Simula gave classes, Algol68 operating overloading, references, and the
ability to declare variables anywhere in a block, and BCPL gave // comments.”
He says a bit more about // comments on page 93, including an example of how they
introduced an incompatibility with C.