Created
February 11, 2020 23:03
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#include <iomanip> | |
#include <iostream> | |
#include <string> | |
#include <type_traits> | |
#include <variant> | |
#include <vector> | |
// the variant to visit | |
using var_t = std::variant<int, long, double, std::string>; | |
// helper type for the visitor #4 | |
template<class... Ts> struct overloaded : Ts... { using Ts::operator()...; }; | |
template<class... Ts> overloaded(Ts...) -> overloaded<Ts...>; | |
int main() { | |
std::vector<var_t> vec = {10, 15l, 1.5, "hello"}; | |
for (auto& v: vec) { | |
// 4. another type-matching visitor: a class with 3 overloaded operator()'s | |
std::visit(overloaded { | |
[](auto arg) { std::cout << arg << ' '; }, | |
[](double arg) { std::cout << std::fixed << arg << ' '; }, | |
[](const std::string& arg) { std::cout << std::quoted(arg) << ' '; }, | |
}, v); | |
} | |
} |
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