Std::cin is the global stream object provided by the C++ standard library for reading from the standard input stream.
Std::cout is the global stream object provided by the C++ standard library for writing to the standard output stream.
Little preferable situations
"Scanf is faster than cin printf is faster than cout etc"
from question "Why are many VMs written in C when they look like they have C++ features?"
"There are obviously situations where in c++ scanf is preferable to cin i was wondering if there are any situations where printf is more practical than cout"
from question "Are there any major advantages to using printf() over cout in C++?"
"Using printf isn t faster than cout but scanf is a little faster than cin 0.04s + - 0.05"
from question "Faster input and output"