test.java

package tester;
import java.util.Scanner;

public class tester {
	Scanner sc = new Scanner(System.in);

	public tester() {
		String number;
		System.out.print("Enter a 10-digit phone number: ");
		number = sc.next();
		String formattedNumber = phoneNumberFormat(number);
		System.out.println("The number you entered is: " + formattedNumber);

	}

	public String phoneNumberFormat(String number) {
		String firstThreeDigits = number.substring(0, 3);
		String middleThreeDigits = number.substring(3, 6);
		String lastFourDigits = number.substring(6, 10);

		return "(" + firstThreeDigits + ") " + middleThreeDigits + "-" + lastFourDigits;
	}


	public static void main(String[] args) {
		 new tester();
	}

}