*6.21 (phone by keyboard) the international standard letter / number matching diagram is shown in the programming exercise 4.15. Write a method to return the number of a given capital letter, as follows:

int getNumber(char uppercaseLetter)

Write a test program to prompt the user to enter a phone number in the form of a string. The number you enter may contain letters. The program translates letters (uppercase or lowercase) into a number, and then keeps the other characters unchanged.

*6.21(Phone keypads)The international standard letter/number mapping for telephones is given in Programming Exercise 4.15. Write a method that returns a number, given an uppercase letter, as follows:

int getNumber(char uppercaseLetter)

Write a test program that prompts the user to enter a phone number as a string. The input number may contain letters. The program translates a letter (uppercase or lowercase) to a digit and leaves all other characters intact.

Here is the reference answer code:

// https://cn.fankuiba.com

import java.util.Scanner;

public class Ans6_21_page201 {
    public static void main(String[] args) {
        Scanner input = new Scanner(System.in);
        System.out.print("Enter a string: ");
        String phoneNumber = input.nextLine().toUpperCase();
        for (int i =0; i < phoneNumber.length(); i++) {
            if (Character.isDigit(phoneNumber.charAt(i))) {
                System.out.print(phoneNumber.charAt(i));
            }
            else if (getNumber(phoneNumber.charAt(i)) == 1)
                System.out.print("-");
            else
                System.out.print(getNumber(phoneNumber.charAt(i)));
        }
    }
    public static int getNumber(char uppercaseLetter) {
        int num = 99;
        switch (uppercaseLetter+"") {
            case "-":
                num = 1;
                break;
            case "A":
                num = 2;
                break;
            case "B":
                num = 2;
                break;
            case "C":
                num = 2;
                break;
            case "D":
                num = 3;
                break;
            case "E":
                num = 3;
                break;
            case "F":
                num = 3;
                break;
            case "G":
                num = 4;
                break;
            case "H":
                num = 4;
                break;
            case "I":
                num = 4;
                break;
            case "J":
                num = 5;
                break;
            case "K":
                num = 5;
                break;
            case "L":
                num = 5;
                break;
            case "M":
                num = 6;
                break;
            case "N":
                num = 6;
                break;
            case "O":
                num = 6;
                break;
            case "P":
                num = 7;
                break;
            case "Q":
                num = 7;
                break;
            case "R":
                num = 7;
                break;
            case "S":
                num = 7;
                break;
            case "T":
                num = 8;
                break;
            case "U":
                num = 8;
                break;
            case "V":
                num = 8;
                break;
            case "W":
                num = 9;
                break;
            case "X":
                num = 9;
                break;
            case "Y":
                num = 9;
                break;
            case "Z":
                num = 9;
        }
        return num;
    }
}

Applicable to Java language programming and data structure (basic part) (the 11th edition of the original book) Java language programming (basic part) (the 10th / 11th edition of the original book)
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