In java, how to get input from user?

Question

During your math class, you are given a task to calculate the perimeter of a circle.
You decide to write a small program that will take the radius as input, and will calculate and print the perimeter for you.
The value for π (pi) is already defined.
Sample Input
4
Sample Output
25.12

Answer 1

Scanner myScanner = new Scanner(System.in);
System.out.println(2*3.14*myScanner.nextInt());