题解 | 表示数字

#include <iostream>
using namespace std;

int main() {
    string s;

    while (cin >> s) {
        string ret = "";
        for (int i = 0; i < s.size() - 1; i++) {
            if ((!isdigit(s[i]) && isdigit(s[i + 1])) || (isdigit(s[i]) && !isdigit(s[i + 1])))  {
                ret += s[i];
                ret += "*";
            } else
                ret += s[i];
        }
        ret += s[s.size() - 1];

        if (isdigit(s[0]))
            ret = "*" + ret;

        if (isdigit(s[s.size() - 1])) {
            ret += "*";
        }

        cout << ret << endl;
    }

}