This article is from the alt.comp.lang.learn.c-c++ Frequently Asked Questions. Compiled by Sunil Rao email@example.com.
C and C++ are languages that are not tied down to a particular platform. This means that, with care, it is possible to write useful code in either of these languages that will run on different platforms without modification.
That is not to say that ALL code written in these languages must conform strictly to the standards - in practice it is sometimes neither possible nor desirable to achieve this aim. However, the job of porting code is made easier when any system-specific stuff is carefully packaged or abstracted away, so that it is clear and straightforward to make the necessary changes during a port.
In order to be able to do this effectively, it is important to be aware of what can and can not be done within the realms of the standards set by these languages. That is why a lot of importance is placed on adhering strictly to the standards, at least while learning.