Java实现代码:
import java.util.Scanner;public class Practice_1009 { public static void main(String[] args) { String string = ""; Scanner scanner = new Scanner(system.in); while (scanner.hasNext()) { boolean flag = false; string = scanner.nextLine(); if (string.length() > 30) break; if (string.contains(" ")) break; //判断是否有空格 if (string.equals("End of file")) break; //判断是否结束 String x[] = string.split("\\."); //将输入字符串分离为A、B、C、D形式 for (int i = 0,j = 0; i < x.length && j < x[i].length(); i++) { char num[] = x[i].tochararray(); //把字符串转换为字符数组 if (!Character.isDigit(num[j])) { flag = false; break; } if (Integer.parseInt(x[i]) > 255 || Integer.parseInt(x[i]) < 0) { flag = false; break; } else flag = true; } if (flag) System.out.println("Y"); else System.out.println("N"); } }}还是觉得自己很菜,啥也不会。慢慢来吧。