A function object, or functor, is an object that has operator () defined so that in the following example:

FunctionObjectType fo;
  // ...
fo(...);

the expression fo() is a call of oerator () for the function object fo instead of a call of the function fo().
At first, you could consider a function object as an ordinary function that is written in a more complicated way. Instead of writing all the function statemetns inside the function body:

void fo() {
 statements
}

your write them inside the body of operator () of the function object class:

class FunctionObjectType {
 public:
       void operator() {
           statements
       }
}

This kind of definition is more complicated but has three important advantages:

• A function object might be smarter because it may have a state.
• Each function object has its owen type. Thus , you can pass the type of function object to a template to specify a certain behavior.
• A function object is usually faster than a function pointer.

How can I autoformat/indent C++ code in vim?

https://stackoverflow.com/questions/2355834/how-can-i-autoformat-indent-c-code-in-vim

How can I autoformat/indent C code in vim?

In this implementation -std=gnu++11 or -std=c++11 flags must be used to enable language and library features.

See Also

1. How to restrict dynamic allocation of objects in C++?

An enumeration is a set of named interger contants that specify all the legal values a variable of that type may have.

the gneral form for enumerations is:

enum enum-type-name {enumeration list} variable_list;

C++ defines five casting operators, The first is the traditional-style cast inherited from c.

The remaning four:

• dynamic_cast
• const_cast
• reinterpret_cast
• static_cast

Many options are available for GDB itself: please see "GDB features for C++" in the GDB documentation. Also recommended:
the other parts of this manual.