what is the cin exactly?

Question

what is the cin exactly?

Answer 1

cout and cin are not key words in the C++ language. They are VARIABLE'S, instances of classes, that have been declared in <iostream>. 
cout--- is a variable of type.  ostream. 
cin---- is a variable of type.  istream.

Answer 2

cin allows the user to input a value for an existing variable. E.g: int myVar; cin>>var. if I put 5, the variable myVar now has the variable 5.

Answer 3

cin is used to get string or variable data from the user

Answer 4

Cin and Cout are telling how to obtain and display information

Answer 5

cin pronounced "see -in" is used to take data from users to process it for result or output

Answer 6

cin is used to get input from the user

Answer 7

cin is like input in python
if you have some knowlegde on python