Which of the following is NOT a primitive data type in C++?

In C++, primitive data types are the basic data types provided by the language that represent single values. These include types like float, double, and char.

Float and double are both used to represent floating-point numbers, where float typically offers a single-precision floating-point representation and double provides double-precision. Char represents a single character, which is typically enclosed in single quotes, such as 'a' or 'Z'.

On the other hand, a string is not a primitive data type in C++. Instead, it is a more complex data type that is typically implemented as a class, such as the std::string class in the C++ Standard Library. This class provides an array of functions for manipulating sequences of characters, but it is built on top of the primitive types, rather than being one itself. Therefore, the string type is considered a composite or derived type rather than a primitive one.

This distinction is crucial for understanding how data types operate in C++. While primitive types provide performance benefits in terms of memory and processing speed, composite types offer more functionality and flexibility for managing collections of data.