Question

IN JAVA pls

Standard telephone keypads contain the digits zero through nine. The numbers two through
nine each have 3~4 letters (case insensitive) associated with them. Many people find it
difficult to memorize phone numbers, so they use the correspondence between digits and
letters to develop seven-letter words that correspond to their phone numbers. For example, a
person whose telephone number is 686-2377 might remember it as "NUMBERS."
Digit Letters
2 A B C
3 D E F
4 G H I
5 J K L
6 M N O
7 P Q R S
8 T U V
9 W X Y Z
2. Each seven-letter word corresponds to exactly one seven-digit telephone number, but a
seven-digit number corresponds to many seven-letter strings, most of which are not words.
3. In this project you will develop a program which will find all the corresponding English
words given any specific telephone number. Here are the detailed requirements:
a. create a static void test() method.
b. The test method will first ask the user to type in through keyboard a 7-digit telephone
number.
c. If the number typed in by the user is not 7 digits or the number contains some number
of the digit ‘0’ or ‘1’, then your program reports an error and asks to type in another
number.
d. If the number typed in by the user is a 7-digit telephone number made up of the digits
‘2’ through ‘9’, then your program will print out all the English words corresponding
to the telephone number (and the total number of them), using the given English
word library in the EnglishWordList.txt”.

EnglishWordList.txt contains the following words

abalone

abandon

abasers

abashes

ablates

caffein

Answer 1

import java.io.File;
import java.io.FileNotFoundException;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.Scanner;
public class StringsFromPhoneDigits {
   public static void test()
   {
       //for numbers adding the map corresponding key pad string for key pad numbers
       HashMap<Character,String> map = new HashMap<Character,String>();
map.put('1', "");
map.put('2',"abc");
map.put('3',"def");
map.put('4',"ghi");
map.put('5',"jkl");
map.put('6',"mno");
map.put('7',"pqrs");
map.put('8',"tuv");
map.put('9',"wxyz");
map.put('0', "");
  
//taking valid input from the user
       System.out.print("Enter a 7-digit telephone number :");
       Scanner input = new Scanner(System.in);
       String digits = input.next();
       boolean result = true;
       while(true)
       {
           if(digits.matches("^[2-9]{7}$")) {
               break;
           }
           else {
               System.out.println("an error occured with your input please enter another number");
               System.out.print("Enter a 7-digit telephone number :");
               digits = input.next();
           }
       }
      
       //processing input for getting possible words with matches input string
       ArrayList<String> res = new ArrayList<String>();
ArrayList<String> preres = new ArrayList<String>();
res.add("");
for(int i = 0; i < digits.length(); i++) {
String letters = map.get(digits.charAt(i));
if (letters.length() == 0)
continue;
for(String str : res) {
for(int j = 0; j < letters.length(); j++)
preres.add(str + letters.charAt(j));
}
res = preres;
preres = new ArrayList<String>();
}
  
   //taking data from the file
   ArrayList<String> stringsFromFile = new ArrayList<String>();
   System.out.println("\nThe Words From EnglishWordList.txt are\n--------------------------------");
   File file = new File("C:\\Users\\Mirchi\\Desktop\\chegg\\TextFiles\\EnglishWordList.txt");
   try {
   Scanner sc = new Scanner(file);
     
   while (sc.hasNextLine()) {
   String i = sc.nextLine();
   stringsFromFile.add(i);
   System.out.println(i);
   }
   sc.close();
   }
   catch (FileNotFoundException e) {
   e.printStackTrace();
   }
  
   //checking from the file weather that words are there are not
   int count = 0;
   for(String i:res) {
       if(stringsFromFile.contains(i)) {
           count++;
       }
   }
   if(count!=0) {
       System.out.println("\n\nTotal Count of words form with given phone digits are = "+count);
       System.out.println("\nThe Result words are\n----------------");
       for(String i:res) {
          if(stringsFromFile.contains(i)) {
              System.out.println(i);
          }
      }
   }
   //if strings are not there in the file printing all possible words
   else {
       System.out.println("\nThere is no match with result strings with the file");
       System.out.println("\n\nTotal Count of words form with given phone digits are = "+res.size());
      System.out.println("The Words are\n----------------");
       for(String i:res) {
              System.out.println(i);
      }
   }
   }

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