Cout is used to show and cin is used to ...?

Answer 1

Take in user input.

int age;
cout << "Enter your age: ";
cin >> age;
cout << "You are " << age << " years old";

Answer 2

If you know C#, "cout" is equivalent to "Console.Write()" and "cin" is equivalent to "Console.ReadLine()".
In Python, "cout" is equivalent to "print()" and "cin" is equivalent to "input".