C++ remains the archetypal "high level" computer language (that is, one that preserves the features of natural, human language), and it is still used by millions of programmers. Many of the systems and applications of the PC and Internet eras were written in C++. For all that, the language remains controversial, largely because it is notoriously difficult to learn and use, and also because Stroustrup's design allows developers to make serious programming mistakes in the interest of preserving their freedom.