Answer 1

Go here and complete your Course. Atlast you will know.

https://www.sololearn.com/learn/CPlusPlus/1602/

Answer 2

In C ++, cout is the output stream (usually the screen) and cin is the input stream (usually the keyboard).

Answer 3

cout is output statement its is written using insertion operator (<<) .
cin is input statement its is written using extraction operator(>>).

Answer 4

https://en.cppreference.com/w/cpp/io/cout