Answer:
Kindly note that, you're to replace "at" with shift 2 as the brainly text editor can't take the symbol
Explanation:
Here is the completed code for the problem in the question above.
// PinWordEnumerator.java
import java.util.Scanner;
public class PinWordEnumerator {
public static void main(String[] args) {
Scanner scanner = new Scanner(System.in);
System.out.print("Enter pin number: ");
String num = scanner.nextLine();
System.out.println();
System.out.printf("The keypad encodings for %s are:%n", num);
enumerateWords(num);
}
/**
* method to return a character array containing all possible keypad
* encodings for a digit in a standard phone
*/
static char[] getKeysForButton(int n) {
switch (n) {
case 0:
return new char[] { ' ' }; //returning only space
case 1:
return new char[] { '.' }; //returning only dot
case 2:
//button 2 contains A, B and C keys
return new char[] { 'A', 'B', 'C' };
case 3:
return new char[] { 'D', 'E', 'F' };
case 4:
return new char[] { 'G', 'H', 'I' };
case 5:
return new char[] { 'J', 'K', 'L' };
case 6:
return new char[] { 'M', 'N', 'O' };
case 7:
return new char[] { 'P', 'Q', 'R', 'S' };
case 8:
return new char[] { 'T', 'U', 'V' };
case 9:
return new char[] { 'W', 'X', 'Y', 'Z' };
}
return null;
}
/**
* method to enumerate words
*
* "at"param num
* - String containing pin numbers, assuming it has only numbers
*/
static void enumerateWords(String num) {
/**
* calling the recursive method to perform the enumeration
*/
if (num != null)
enumerateWords(num, "");
}
/**
* the main method which performs the recursion
*
* "at"param num
* - current number
* "at"param text
* - text containing converted spellings
*/
static void enumerateWords(String num, String text) {
if (num.length() == 0) {
// base case, displaying the text
System.out.println(text);
} else {
// finding the digit at 0th position
int digit = num.charAt(0) - '0';
// finding possible phone keys for this digit
char letters[] = getKeysForButton(digit);
if (letters != null) {
// looping through all possible keys
for (int i = 0; i < letters.length; i++) {
/**
* appending the current letter to the text and calling the
* recursive method also neglecting the first letter of
* current 'num' string
*/
enumerateWords(num.substring(1), text + letters[i]);
}
}
}
}
}
/*OUTPUT*/
Enter pin number: 5282
The keypad encodings for 5282 are:
JATA
JATB
JATC
JAUA
JAUB
JAUC
JAVA
JAVB
JAVC
JBTA
JBTB
JBTC
JBUA
JBUB
JBUC
JBVA
JBVB
JBVC
JCTA
JCTB
JCTC
JCUA
JCUB
JCUC
JCVA
JCVB
JCVC
KATA
KATB
KATC
KAUA
KAUB
KAUC
KAVA
KAVB
KAVC
KBTA
KBTB
KBTC
KBUA
KBUB
KBUC
KBVA
KBVB
KBVC
KCTA
KCTB
KCTC
KCUA
KCUB
KCUC
KCVA
KCVB
KCVC
LATA
LATB
LATC
LAUA
LAUB
LAUC
LAVA
LAVB
LAVC
LBTA
LBTB
LBTC
LBUA
LBUB
LBUC
LBVA
LBVB
LBVC
LCTA
LCTB
LCTC
LCUA
LCUB
LCUC
LCVA
LCVB
LCVC
