java基础-给出一个随机字符串，判断有多少字母？多少数字？

package com.string;

import java.util.Scanner;

public class Character_Judge {
 public static void main(String[] args) {
  System.out.println("请随机输入一段字符串");
  Scanner scan = new Scanner(System.in);
  String str = scan.nextLine();
  char s[] = str.toCharArray();
  int char_num=0;//计算字母
  int num = 0;//计算数字
  int other = 0;//计算其他字符

  for(int i=0;i<s.length;i++)
  {
   if (s[i]<='9'&&s[i]>='0')
    num++;
   else if (s[i]>='a'&&s[i]<='z'||s[i]>='A'&&s[i]<='Z')
    char_num++;
   else
    other++;
  }

  System.out.println("字符有"+char_num+"个;数字有"+num+"个;其他字符有"+other+"个");
 }
}