Is Unix coded in C or C++ or both?
c, c++, unix
Solution
Unix was first created at Bell Labs in 1969, well before C++ was conceived. (Src: Unix), you can confirm this by reading Lions' Commentary on Unix, or the BSD 4.4-Lite (which is similar to BSD Net/2) which is available in tarball or via cvs (from FreeBSD). Or the archives from The Unix Heritage Society which is from the very old Bell Labs / AT&T versions.
Bjarne Stroustrup created C++ in approximately 1983, prior to that he worked on "C with Classes", according to History of C++. Confirmed from Bjarne Stroustrup's FAQ, and the earliest date for C with Classes was 1979.
I hope that clarifies the impossibility of the idea that Unix was based upon C++. Note that Object-Oriented languages have been around since 1960s in Simula 67, so don't confuse objects and classes with C++.
Problem
Many system calls in Unix use overloading and default variables. This concept is absent in C, so Unix is coded in C++ also right?