Some test code to see behavior of `std::variant` and `std::visit`

cpp_variant_and_visit.cpp

#include <iostream>
#include <string>
#include <variant>


template<class... Types>
struct overloaded : Types... { using Types::operator()...; };

template<class... Types>
overloaded(Types...)->overloaded<Types...>;

using VARIANT = std::variant<int, wchar_t*, char*, std::wstring, std::string, bool, std::nullptr_t>;


struct SomeClass {
    void _func(const int arg) {
        std::cout << "int overload called" << std::endl;
    }

    void _func(const std::string& arg) {
        std::cout << "string overload called" << std::endl;
    }

    void _func(const std::wstring& arg) {
        std::cout << "wstring overload called" << std::endl;
    }

    void _func(const char* arg) {
        std::cout << "char* overload called" << std::endl;
    }

    void _func(const wchar_t* arg) {
        std::cout << "wchar_t* overload called" << std::endl;
    }

    void _func(bool arg) {
        std::cout << "Boolean overload called" << std::endl;
    }

    void _func (std::nullptr_t arg) {
        std::cout << "nullptr_t overload called" << std::endl;
    }
    
    void func(const VARIANT& arg) {
        std::cout << "Variant called" << std::endl;

        std::visit(overloaded{
            [&](const int arg) { _func(arg); },
            [&](const char* arg) { _func(arg); },
            [&](const wchar_t* arg) { _func(arg); },
            [&](const std::string& arg) { _func(arg); },
            [&](const std::wstring& arg) { _func(arg); },
            [&](const bool arg) { _func(arg); },
            [&](const std::nullptr_t& arg) { _func(arg); }
        }, arg);
    }
};




int main() {
    std::string temp = "mew";
    SomeClass a;

    a.func(1);
    a.func("ABCD");
    a.func(temp);
    a.func(L"ABCD");
    a.func(true);
    a.func(nullptr);
}

Live

Output:

ASM generation compiler returned: 0
Execution build compiler returned: 0
Program returned: 0
Variant called
int overload called
Variant called
string overload called
Variant called
string overload called
Variant called
wstring overload called
Variant called
Boolean overload called
Variant called
nullptr_t overload called