With Concert Technology, in order to change the type of a variable in a model, you actually create an extractable object (an instance of IloConversion, documented in the Concert Technology Reference Manual) and add that object to the model.

In the example, when the application needs to change the elements of Cut (an array of numeric variables) from their default type of ILOFLOAT to integer (type ILOINT), it creates an instance of IloConversion, applies it the array Cut, and adds the conversion to the model, cutOpt, like this:

cutOpt.add(IloConversion(env, Cut, ILOINT));