Libraries are helpful tools that programmers use to perform various repetitive tasks. Libraries are also a collection of related classes and functions that are very common and used often. With libraries, programmers do not have to write these functions themselves hence lots of time and efforts is saved.
IT++ is a library for C++ programmers that comes with classes and functions for mathematical codes and communications. The library has a large pool of functions and classes that deal with the simulation of communication systems that are written in C++. Indeed, some of the classes included are for signal processing, source coding of communication, and other basic mathematical functions.
There are even templates you can look at to help you get started. There is no doubt that IT++ is a great assistant for a large variety of C++ work.