This document discusses different data types in programming languages. It defines a data type as a set of values plus operations that can be performed on those values. There are two main types of data types: built-in/primitive types that are included in the language and class/programmer-defined types. Integer is one of the built-in data types that represents whole numbers and has specific valid value formats without decimals or commas. The escape character \ is also discussed as having a special meaning in C++ to change the interpretation of subsequent characters.