# Scope ?
# In C++ before using any variables, functions, classes and types or compound types needs to be declare first somewhere in your C++ program.
# Where you declare or define them, decides their visibility.
# Visibility means whether you can use that everywhere or somewhere in your program.
# GLOBAL variables ?
# A list of variables that can be used anywhere in your program without even declaring and defining them are GLOBAL variables.
# LOCAL variables ?
# Those who exists in some defined code blocks.
# outside that code block they does not exists.
# sometimes local variables are used to protect GLOBAL variables.
# In C++ you can declare a identifier once within a single scope.
# In C++ visibility of Identifiers is influenced by curly brackets that is used to group more than one C++ statements together.
# This means you can create a new scope/world for your new/old variables.
# Namespace ?
# Namespace is a C++ Identifier that used to group some code functionality within a single name of identifier.
# You must be familiar with std that is a namespace in C++ that holds all
standard C++ functions/routines, Global variables, Classes.
# while printing something to Console/Terminal you use :-
std::cout << "Hello world!" << endl;
# This is how you can access any function or routine from std namespace even without importing anything from there.
# If you know Java/C#, than you may be familiar with this concept.
# Importing selected Identifiers from any Namespace ?
# Importing everything from selected Namespace into current scope ?
# scope matters while importing anything from any Namespace.
# Static , Global, and Local variables ?
http://www.cplusplus.com/doc/tutorial/namespaces/
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