如何在C++中解析具有不同字段数的行

#include<iostream>
#include <sstream>
#include<vector>
#include<string>

int main() {
    std::string line;
    std::getline(std::cin, line);
    std::istringstream iss(line);
    std::vector<std::string> fields;
    std::string field;

    while (std::getline(iss, field, ' ')) {
        fields.push_back(field);
    }

    for (const auto& f : fields) {
        std::cout << f << std::endl;
    }

    return 0;
}

#include<iostream>
#include<regex>
#include<vector>
#include<string>

int main() {
    std::string line;
    std::getline(std::cin, line);
    std::regex re("\\s+");
    std::sregex_token_iterator it{line.begin(), line.end(), re, -1};
    std::vector<std::string> fields{it, {}};

    for (const auto& f : fields) {
        std::cout << f << std::endl;
    }

    return 0;
}