Practically everything ok@quintus cites as proving that C does not
descend from Algol 68 is true, yet there was influence, much of
it so subtle that it is hard to recover even when I think hard.
In particular, the union type (a late addition to C) does owe to A68,
not in any details, but in the idea of having such a type at all.
More deeply, the type structure in general and even, in some strange
way, the declaration syntax (the type-constructor part) was inspired by A68.
And yes, of course, "long".
Mostly, of course, C is Thompsonized BCPL (that is, B) with types.
You don't have to look too hard to find PL/1 and Fortran, either.
Dennis Ritchie