计算一个字符串中字母的个数

import java.util.Scanner;

public class BookTest6_20 {
public static void main(String[] args) {
Scanner input = new Scanner(System.in);
System.out.println(“请输入一个字符串”);
String s = input.nextLine();

    System.out.println("这个字符串中字母的个数为" + countLetters(s) + "个");
}

public static int countLetters(String s) {
    int count = 0;
    for (int x = 0; x < s.length(); x++) {
        //判断字符是否是字母,依次判断索引0到length-1的字符
        if (Character.isLetter(s.charAt(x))) {
            count++;
        }
    }

    return count;
}

}