To learn C++, first start by learning C. K&R Second Edition
http://www.amazon.com/Programming-Language-Brian-W-Kernighan/dp/0131103628/ref=sr_1_1?ie=UTF8&qid=1427999620&sr=8-1&keywords=the+c+programming+languageEvery construct, technique, method, done in C++ is a wrapper around the C language. Every mechanism in C++, along with
every construct, method, technique of other languages can be accomplished in C. with simpler code, and most other languages are written in C.
Portable code is written in C not C++. Most other languages, such as PHP, Javascript, JSON, and most any other respectable language, follows C style constructs. I find it interesting that most all other languages appear to be a variation on C when C already does everything all those other languages do, and in simpler more controllable form.