java square a number

Scanner in=new Scanner(System.in);
int num=in.nextInt();
System.out.println(Math.sqrt(num)); // the sqrt function gives a value in 'double' data type.

//To square:
int i = 2;
int square = Math.pow(i, 2);

//To cube:
int i = 2;
int cube = Math.pow(i, 3);

//To nth power:
int i = 2;
int nthPower = Math.pow(i, 4);