std::variant cout in C++

Question

I am relatively new to CPP and have recently stumbled upon std::variant for C++17.

However, I am unable to use the << operator on such type of data.

Considering

#include <iostream>
#include <variant>
#include <string>
using namespace std;
int main() {

    variant<int, string> a = "Hello";
    cout<<a;
}

I am unable to print the output. Is there any short way of doing this? Thank you so much in advance.

Answer 1

use std::get

#include <iostream>
#include <variant>
#include <string>
using namespace std;

int main() {

    variant<int, string> a = "Hello";
    cout << std::get<string>(a);
}

If you want to get automatically, it can't be done without knowing its type. Maybe you can try this.

string s = "Hello";
variant<int, string> a = s;

cout << std::get<decltype(s)>(a);