I use cin with the extraction operator >> to read values from the keyboard. The statement cin >> x; waits for the user to type something and press Enter, then stores that value in variable x.
Here is a complete example: int age; cin >> age; pauses execution, reads an integer from the user, and stores it. If the user types 25 and presses Enter, age becomes 25. The extraction operator >> points toward the variable, showing the direction data flows.
Think of cin as a stream of characters coming from the keyboard, and >> extracts values from that stream.