cin variable — Normal input stream
extern istream cin
The cin object is a standard input stream associated with the C stdin file. It is used for normal program input. It is tied to cout (see the tie member function of basic_ios in <ios>).
cin
stdin
cout
tie
basic_ios
<ios>
wcin variable, basic_ios in <ios> , istream in <istream>
istream
<istream>