Figure 1.1 shows a program using the CPLEX Concert Technology Library to solve optimization problems. The optimization part of the user's application program is captured in a set of interacting C++ objects that the application creates and controls. These objects can be divided into two categories:

Modeling objects are used to define the optimization problem. Generally an application creates several modeling objects to specify the optimization problems. Those objects are grouped into an IloModel object representing the complete optimization problem.
IloCplex objects are used to solve models created with the modeling objects. An IloCplex object reads a model and extracts its data to the appropriate representation for the CPLEX optimizer. Then the IloCplex object is ready to solve the model it extracted and be queried for solution information.

Figure 1.1 A View of CPLEX Concert Technology Library