Java String输出限制String到Alphabet的范围

Question

我目前正在做一个练习(不是任何人放弃之前的作业)，我被困在问题的最后部分。

问题是:

Write a program which will input a String from the keyboard, output the number of
seperate words, where a word is one or more characters seperated by spaces. Your
program should only count words as groups of characters in the rang A..Z and a..z

从我的代码可以看出，我可以毫无问题地完成第一部分:

导入java.util.Scanner;

public class Exercise10 {

public static void main(String[] args) {
    String input;
    int counter = 0;
    Scanner keyboard = new Scanner(System.in);

    System.out.println("Please enter your text: ");
    input = keyboard.nextLine();

    for(int i = 0; i < input.length(); i++){

        if(input.charAt(i) == ' '){
            counter++;
            }   
    }

    System.out.println(counter + 1);
    keyboard.close();

    }
 }

但是让我感到困惑的部分是:

Your program should only count words as groups of characters in the rang A..Z and 
a..z

遇到这种情况我该怎么办？

Answer 1

我不会给你一个完整的答案，但这里有两个提示。

与其计算空格，不如考虑拆分字符串并循环遍历拆分后的每个元素:

Documentation

一旦您将 String 拆分并可以遍历元素，遍历每个元素中的每个字符以检查它是否是字母:

Hint