{"title":"\u3010\u4e00\u4eba C++20 Advent Calendar 2019\u3011\u5b9a\u6570\u5f0f\u304b\u3089\u306e\u4eee\u60f3\u95a2\u6570\u306e\u547c\u3073\u51fa\u3057\u3092\u8a31\u53ef\u30106\u65e5\u76ee\u3011","html":"<iframe src=\"https://hatenablog-parts.com/embed?url=https%3A%2F%2Fsecret-garden.hatenablog.com%2Fentry%2F2019%2F12%2F06%2F232434\" title=\"\u3010\u4e00\u4eba C++20 Advent Calendar 2019\u3011\u5b9a\u6570\u5f0f\u304b\u3089\u306e\u4eee\u60f3\u95a2\u6570\u306e\u547c\u3073\u51fa\u3057\u3092\u8a31\u53ef\u30106\u65e5\u76ee\u3011 - 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>","version":"1.0","blog_url":"https://secret-garden.hatenablog.com/","width":"100%","url":"https://secret-garden.hatenablog.com/entry/2019/12/06/232434","blog_title":"Secret Garden(Instrumental)","author_name":"osyo-manga","height":"190","description":"\u4e00\u4eba C++20 Advent Calendar 2019 6\u65e5\u76ee\u306e\u8a18\u4e8b\u306b\u306a\u308a\u307e\u3059\u3002 \u5b9a\u6570\u5f0f\u304b\u3089\u306e\u4eee\u60f3\u95a2\u6570\u306e\u547c\u3073\u51fa\u3057\u3092\u8a31\u53ef \u5b9a\u6570\u5f0f\u3067\u306e\u4eee\u60f3\u95a2\u6570\u547c\u3073\u51fa\u3057\u304c\u53ef\u80fd\u306b\u306a\u308a\u307e\u3057\u305f\u3002\u306a\u308a\u307e\u3057\u305f\uff01 struct X { virtual int value() const = 0; }; constexpr int twice(X const& x) { // \u53c2\u7167\u3092\u7d4c\u7531\u3057\u3066\u4eee\u60f3\u95a2\u6570\u3092\u5b9a\u6570\u5f0f\u3067\u547c\u3073\u51fa\u3059\u3053\u3068\u304c\u53ef\u80fd return x.value() + x.value(); } struct Y : X { constexpr int value() const { return 42; } }; int mai\u2026","image_url":null,"provider_url":"https://hatena.blog","published":"2019-12-06 23:24:34","categories":["C++","C++20"],"type":"rich","author_url":"https://blog.hatena.ne.jp/osyo-manga/","provider_name":"Hatena Blog"}