Ability to parse date w/o libfmt

test_date_parser_wo_fmt.cpp

#include <iomanip>
#include <iostream>
#include <string>
#include <sstream>
#include <chrono>

using namespace std;

const char * time_format = "%Y-%m-%d";

auto string2date(string src) {
    tm tm_p = {};
    stringstream buf(src);
    buf >> get_time(&tm_p, time_format);
    return chrono::system_clock::from_time_t(mktime(&tm_p));
}

auto date2string(chrono::system_clock::time_point t) {
    auto t_raw = chrono::system_clock::to_time_t(t);
    stringstream buf;
    buf << put_time(localtime(&t_raw), time_format);
    return buf.str();
}

int main() {
    string test = "2023-05-03";

    auto time_p = string2date(test);
    auto to_str = date2string(time_p);

    if (test == to_str) cout << "Passed" << endl;
    else cerr << "Error" << endl;

    return 0;
}

g++ -std=c++20 test_date_parser_wo_fmt.cpp