• C++11 is the ISO C++ standard ratified in 2011. The previous standard is often referred to as C++98 or C++03; the differences between C++98 and C++03 are so few and so technical that they ought not concern users. C++14 is the informal name for a recent revision of the C++ standard. It is intended to be a small extension over C++11, featuring mainly bug fixes and small improvements.
• Differences between a class and a struct in C++ are that structs have default public members and bases and classes have default private members and bases. Both classes and structs can have a mixture of public and private members, can use inheritance, and can have member functions. Classes create a namespace that also encapsulate the functions for manipulating its data elements. Classes may not be used when interfacing with C, because C does not have a concept of classes.

• Maps

Lets consider your /usr/local/lib/libYARP_OS.a. What you can do is, have -L/usr/local/lib/ in your makefile as one of the variables. And then you can have -lYARP_SO appended to the LDLIBS.

-L is for path to the lib and -l is the lib name here libYARP_OS.a will be passed as -lYARP_OS. On command line you would do something like: gcc -o main main.c -L/usr/local/lib/ -lYARP_SO. This should give you an idea.

ofRectangle rectangle = ofGetCurrentViewport();
//is the same as
auto rectangle = ofGetCurrentViewport();
 
//and
 
const ofRectangle rectangle = ofGetCurrentViewport();
//is the same as
const auto rectangle = ofGetCurrentViewport();
 
float x = rectangle.x;
//is the same as
auto x = rectangle.x;
 
//and
 
float & x = rectangle.x;
//is the same as
auto & x = rectangle.x;

for (auto mySelfie : mySelfies) { ... }
// To use a reference rather than a copy
for(auto & mySelfie : mySelfies) { ... }

This does not produces an error:

class BuildingProjectionMapper {
public:
//...
    virtual void mapTheGreekColumns();
//...
};
 
class AutoBuildingProjectionMapper : public BuildingProjectionMapper {
public:
	void mapTheGreekColums(); // woops, I spelt column incorrectly
};

To solve this:

class AutoBuildingProjectionMapper : public BuildingProjectionMapper {
public:
	void mapTheGreekColums() override;
};

• Do not use this inside of a constructor.