第六章第二十一题（电话按键盘）(Phone keypads) - 编程练习题答案

*6.21（电话按键盘）国际标准的字母/数字匹配图如编程练习题4.15所示，编写一个方法，返回给定大写字母的数字，如下所示：

int getnumber(char uppercaseletter)

编写一个测试程序，提示用户输入字符串形式的电话号码。输入的数字可能会包含字母。程序将字母（大写或者小写）翻译成一个数字，然后保持其他字符不变。

*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.

下面是参考答案代码:

// 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;
    }
}

适用java语言程序设计与数据结构（基础篇）（原书第11版）java语言程序设计（基础篇）（原书第10/11版）