表示数字

StringBuilder 轻松解决

import java.util.*;

public class Main {


    public Main() {

    }

    public String markNum(String pInStr) {
        StringBuilder res = new StringBuilder();
        for (int i = 0; i < pInStr.length();) {
            // 若发现了数字
            if (pInStr.charAt(i) >= '0' && pInStr.charAt(i) <= '9') {
                res.append('*');
                while (i < pInStr.length() && pInStr.charAt(i) >= '0' && pInStr.charAt(i) <= '9') {
                    res.append(pInStr.charAt(i++));
                }
                res.append('*');
            }
            else {
                res.append(pInStr.charAt(i++));
            }
        }
        return res.toString();
    }

    public static void main(String[] args) {
        Main solution = new Main();
        Scanner in = new Scanner(System.in);
        while (in.hasNextLine()) {
            String pInStr = in.nextLine();
            String res = solution.markNum(pInStr);
            System.out.println(res);
        }

    } 
}