Question

Toll-Free numbers have become so popular that the 800-code prefix has run out of available numbers, so the additional 3-digit prefix 877 has been added. Create a program in java that accepts a 10-digit phone number (no 1 in front) and tells the user if the number is toll-free. Display Not toll-free otherwise. EXAMPLE Input: 8001234567 Toll-free number

Answer 1

Explanation::

• Code in JAVA is given below
• Please read comments for better understanding of the code
• Screenshots of the OUTPUT are given at the end of the code

Code in JAVA::

import java.util.Scanner;

public class Toll {

   public static void main(String[] args) {
       /**
       * Using Scanner class object named sc to take input from the user
       * */
       Scanner sc=new Scanner(System.in);
      
       /**
       * A String variable named number is declared below
       * */
       String number;
      
       /**
       * Prompting user to enter the String number
       * */
       System.out.print("Enter the number : ");
       number=sc.nextLine();
       /**
       * Following while loop checks the validity of the String entered by user
       * Check 1: If length is exactly 10 characters long
       * Check 2: There is no '1' in front
       * */
       while(true) {
           if(number.length()==10 && number.charAt(0)!='1') {
               break;
           }
           System.out.println("Invalid Input!");
           System.out.print("\nEnter the number : ");
           number=sc.nextLine();
       }
       /**
       * Now we check if first three characters are "800" or not
       * Using substring() method we can get the substring of String number
       * */
       String value=number.substring(0, 3);
       if(value.equals("800")) {
           System.out.println("Toll-free number");
       }else {
           System.out.println("Not toll-free otherwise");
       }
      
   }

}

OUTPUT::
TEST CASE 1:

TEST CASE 2:

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