No, there is no language exists between C & C++. As we know that C++ is the superset of C language.
Bjarne Stroustrup wants to mix the capabilities of the C language with OOP. So, he introduces a new object-oriented language by combining the features of two programming languages – C & simula67. Initially, this new language is known as ‘C with Classes’ & later renamed to C++ (an increment to C language). Hence, there is no language as C+.
Additional Info :
C– language – There is a compiler targeted programming language exists with the name C– (C minus minus). What is C– (C minus minus) ?