年轻人不讲码德

import java.util.*;
public class Main {
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        while(sc.hasNext()) {
            String inputStr = sc.nextLine();
            int pi = inputStr.indexOf(".");
            String r = inputStr.substring(0, pi);
            int ri = Integer.parseInt(r);
            String f = inputStr.substring(pi+1);
            int fi = Integer.parseInt(f);
            if( fi>=0 && fi<5 ) {
                System.out.println(ri);
            } else {
                System.out.println(ri+1);
            }
        }
    }
} 

采用字符串截取并转化，菜鸟一枚~