Question

Write a program called telephone.java that prompts the user to enter their phone number using the specific format: (xxx) xxx-xxxx. The program should check whether the input entered is valid. The program must also check for the parenthesis () for the area code (the first three numbers). Example: (702)892-0516 would be correct but 702-892-0516 would not be correct. Example: Enter your phone number: 702-908-1333. 702-908-1333 is a NOT a valid phone number as there are no parenthesis (). Another example: Enter your phone number: (70 –290-8133 (70—290-8133 is NOT a valid phone number. If the entered telephone number is valid the program should return a statement that says the phone number is valid.

Answer 1

Telephone.java

import java.util.Scanner;

public class Telephone {
   public static void main(String[] args) {
       Scanner scan = new Scanner(System.in);
       System.out.println("Enter a telephone number using the specific format: (xxx) xxx-xxxx: ");
       String phone = scan.next();
       if(phone.length() == 13) {
           if(phone.charAt(0) == '(' && phone.charAt(4)==')' && phone.charAt(8) == '-') {
               String firstNum = phone.substring(1,4);
               String secondNum = phone.substring(5,8);
               String thirdNum = phone.substring(9);
               if(firstNum.matches("[0-9]+") && secondNum.matches("[0-9]+")&& thirdNum.matches("[0-9]+")) {
                   System.out.println("Given phone number is valid");
               } else {
                   System.out.println("Given phone number is invalid");
               }
           } else {
               System.out.println("Given phone number is invalid");
           }
       } else {
           System.out.println("Given phone number is invalid");
       }
   }
}

Output:

Enter a telephone number using the specific format: (xxx) xxx-xxxx:
(702)892-0516
Given phone number is valid