答案 0 :(得分:0)
尝试更改
auto tryParseInt(const char* src)->std::optional<int>
{
const char* end = std::strchr(src, 0); // find the terminating null
int parsed;
std::from_chars_result result = std::from_chars(src, end, parsed);
return (!(bool)result.ec && result.ptr == end)
? std::optional<int>{ parsed }
: std::nullopt;
}