题解 | #统计字符#

import java.util.Scanner;

// 注意类名必须为 Main, 不要有任何 package xxx 信息
public class Main {
    public static void main(String[] args) {
        Scanner in = new Scanner(System.in);
        String word = in.nextLine();
        int[] counts = new int[4];

        for (int i = 0; i < word.length(); i++) {
            char c = word.charAt(i);
            if (c == ' ') {
                counts[1]++;
            } else if (Character.isDigit(c)) {
                counts[2]++;
            } else if (Character.isLetter(c)) {
                counts[0]++;
            } else {
                counts[3]++;
            }
        }

        for (int count : counts) {
            System.out.println(count);
        }
    }
}