The CPLEX Optimizer was named after the simplex method implemented in the C programming language.
The CPLEX Optimizer has a modeling layer called Concert that provides interfaces to the C++, C#, and Java languages.
Finally, a stand-alone Interactive Optimizer executable is provided for debugging and other purposes.
The CPLEX Optimizer is accessible through independent modeling systems such as AIMMS, AMPL, GAMS, OptimJ and TOMLAB.
In addition to that AMPL provides an interface to the CPLEX CP Optimizer.