{"blog_title":"Secret Garden(Instrumental)","title":"C++17 \u306e std::optional \u306b\u7121\u52b9\u5024\u3092\u8a2d\u5b9a\u3059\u308b","url":"https://secret-garden.hatenablog.com/entry/2017/06/22/161953","blog_url":"https://secret-garden.hatenablog.com/","categories":["C++"],"published":"2017-06-22 16:19:53","author_name":"osyo-manga","height":"190","provider_name":"Hatena Blog","html":"<iframe src=\"https://hatenablog-parts.com/embed?url=https%3A%2F%2Fsecret-garden.hatenablog.com%2Fentry%2F2017%2F06%2F22%2F161953\" title=\"C++17 \u306e std::optional \u306b\u7121\u52b9\u5024\u3092\u8a2d\u5b9a\u3059\u308b - Secret Garden(Instrumental)\" class=\"embed-card embed-blogcard\" scrolling=\"no\" frameborder=\"0\" style=\"display: block; width: 100%; height: 190px; max-width: 500px; margin: 10px 0px;\"></iframe>","image_url":null,"type":"rich","author_url":"https://blog.hatena.ne.jp/osyo-manga/","version":"1.0","description":"C++17 \u3067\u306f Boost.Optional \u304c\u65b0\u3057\u304f\u6a19\u6e96\u30e9\u30a4\u30d6\u30e9\u30ea\u5165\u308a\u3057\u307e\u3057\u305f\u3002 Boost.Optional \u3067\u7121\u52b9\u5024\u3092\u6307\u5b9a\u3059\u308b\u5834\u5408\u306f boost::none \u3092\u4f7f\u3063\u3066\u3044\u305f\u3093\u3067\u3059\u304c\u3001\u6a19\u6e96\u30e9\u30a4\u30d6\u30e9\u30ea\u306e std::optional \u3067\u306f std::nullopt \u3092\u4f7f\u7528\u3057\u3066\u7121\u52b9\u5024\u3092\u6307\u5b9a\u3057\u307e\u3059\u3002 [\u30bd\u30fc\u30b9\u30b3\u30fc\u30c9] #include <optional> #include <iostream> template<typename T> void print(std::optional<T> const& op){ if( op ){ std::cout << \"OK:\" << * op << s\u2026","provider_url":"https://hatena.blog","width":"100%"}