C++ 20 Lezione 3

#include <iostream>
#include <format>
#include <fstream>
#include <iomanip>
#include <chrono>

using namespace std;

double f() { return 123.456; }

class Cliente {
private:
    string ragioneSociale = "";
public:
    Cliente(string rs) { ragioneSociale = rs; }
    string getRagioneSociale() const {return ragioneSociale;}

};

template <>
struct std::formatter<Cliente> : std::formatter<std::string> {

    auto format(Cliente cli, format_context& ctx) {
        return formatter<string>::format(
            std::format("{}", "[[" + cli.getRagioneSociale()+"]]"), ctx);

    }
};

int main()
{
    const string s1 = "primo placeholder";
    const string s2 = "secondo placeholder";
    const string s3 = "primo placeholder";
    const string s5 = "PLACEHOLDER";
    cout << "12345678901234567890\n";

    //for (int i = 1; i < 20; i++)
        //cout << format("{0:10}{1:10} \n", i * i, i * i * i);
        //cout << format("{0:#10x}{1:#10X} \n", i * i, i * i * i);
        //cout << format("{0:#010x}{1:#10X}{2:*<10}\n", i * i, i * i * i, "ciao");


    auto ora = chrono::system_clock::now();
    cout << format("{:%d-%m-%Y %H:%M}\n", ora);

    ofstream file{ "dati.txt" };
    format_to(ostream_iterator<char>(file), "prova, {}!", s3);
    file.close();

    Cliente c1 =  Cliente("fcamuso incorporated");

    cout << format("{0:-^30}\n", c1);

}