The History
C++ and therefore the standard library have a long history. C++ started in the 1980s of the last millennium and ended now in 2017. Anyone who knows about software development knows how fast our domain evolves. So 30 years is a very long period. You may not be so astonished that the first components of C++, like I/O streams, were designed with a different mindset than the modern Standard Template Library (STL). This evolution in the area of software development in the last 30 years, which you can observe in the C++ standard library, is also an evolution in the way software problems are solved. C++ started as an object-oriented language, then incorporated generic programming with the STL and now has adopted a lot of functional programming ideas.
The first C++ standard library from 1998 had three components. Those were the previously mentioned I/O streams, mainly for file handling, the string library and the Standard Template Library. The Standard Template...