{"id":5056,"date":"2018-02-18T22:37:13","date_gmt":"2018-02-18T13:37:13","guid":{"rendered":"https:\/\/theolizer.com\/wordpress\/?p=5056"},"modified":"2018-02-18T22:37:13","modified_gmt":"2018-02-18T13:37:13","slug":"cpp-school2-19","status":"publish","type":"post","link":"https:\/\/theolizer.com\/cpp-school2\/cpp-school2-19\/","title":{"rendered":"\u7b2c19\u56de CRTP\u3092\u4f7f\u3063\u3066\u307f\u3088\u3046\uff01"},"content":{"rendered":"

\u3053\u3093\u306b\u3061\u306f\u3002\u7530\u539f\u3067\u3059\u3002<\/p>\n

CRTP\u3068\u306fCuriously Recurring Template Pattern\u306e\u982d\u6587\u5b57\u3067\u300c\u5947\u5999\u306b\u518d\u5e30\u3057\u305f\u30c6\u30f3\u30d7\u30ec\u30fc\u30c8\u30d1\u30bf\u30fc\u30f3<\/a>\u300d\u3068\u3082\u8a33\u3055\u308c\u308b\u3088\u3046\u3067\u3059\u3002\u300c\u5947\u5999\u300d\u306f\u300c\u304a\u304b\u3057\u306a\u300d\u3068\u304b\u300c\u5909\u306a\u300d\u306e\u30cb\u30e5\u30a2\u30f3\u30b9\u3067\u306f\u306a\u304f\u3066\u300c\u4e0d\u601d\u8b70\u306a\u300d\u304c\u8fd1\u3044\u3088\u3046\u306b\u601d\u3044\u307e\u3059\u3002C++\u306e\u69d8\u3005\u306a\u6a5f\u80fd\u3068\u540c\u69d8\u3001\u77e5\u3089\u306a\u3044\u3068\u56f0\u308b\u3082\u306e\u3067\u306f\u306a\u3044\u3067\u3059\u304c\u3001\u30c7\u30e1\u30ea\u30c3\u30c8\u306a\u304f\u30d7\u30ed\u30b0\u30e9\u30e0\u3092\u9ad8\u901f\u5316\u3067\u304d\u308b\u30b1\u30fc\u30b9\u304c\u3042\u308b\u306e\u3067\u3001\u6709\u7528\u306a\u30c6\u30af\u30cb\u30c3\u30af\u306e\uff11\u3064\u3067\u3059\u3002\uff08\u3082\u3061\u308d\u3093\u3001\u4ed6\u306e\u6a5f\u80fd\u540c\u69d8\u4f7f\u3048\u306a\u3044\u30b1\u30fc\u30b9\u3082\u3042\u308a\u307e\u3059\u306e\u3067\u9078\u629e\u80a2\u306e\uff11\u3064\u3068\u6349\u3048\u3066\u4e0b\u3055\u3044\u3002\uff09<\/p>\n

\uff11\uff0e\u57fa\u672c\u69cb\u9020<\/h3>\n

\u300c\u30d1\u30bf\u30fc\u30f3\u300d\u3068\u547c\u3070\u308c\u308b\u3088\u3046\u306b\u3001\u8981\u3059\u308b\u306b\u30d7\u30ed\u30b0\u30e9\u30e0\u306e\u5b9a\u578b\u7684\u306a\u69cb\u9020\u3067\u3059\u3002CRTP\u306e\u69cb\u9020\u81ea\u4f53\u306f\u5358\u7d14\u3067\u3059\u3002
\n\u30af\u30e9\u30b9\u30fb\u30c6\u30f3\u30d7\u30ec\u30fc\u30c8\u3092\u57fa\u5e95\u30af\u30e9\u30b9\u3068\u3057\u3001\u305d\u306e\u30c6\u30f3\u30d7\u30ec\u30fc\u30c8\u30fb\u30d1\u30e9\u30e1\u30fc\u30bf\u306b\u6d3e\u751f\u30af\u30e9\u30b9\u3092\u4e0e\u3048\u308b\u3068\u3044\u3046\u69cb\u9020\u3067\u3059\u3002<\/p>\n

\r\ntemplate<class tDerived>\r\nclass CrtpBase\r\n{\r\n};\r\n\r\nclass CrtpDerived : CrtpBase<CrtpDerived>\r\n{\r\n};\r\n<\/pre>\n
\u7b2c\u4e00\u5370\u8c61\u306f\u3001\u4e0d\u601d\u8b70\u306a\u69cb\u9020\u3068\u8a00\u3046\u304b\u4f55\u306e\u5f79\u306b\u7acb\u3064\u306e\u3060\u308d\u3046\u3068\u79c1\u306f\u611f\u3058\u307e\u3057\u305f\u3002<\/p>\n
    \n
  1. \u57fa\u5e95\u30af\u30e9\u30b9\u30fb\u30c6\u30f3\u30d7\u30ec\u30fc\u30c8\u306b\u6d3e\u751f\u30af\u30e9\u30b9\u3092\u4e0e\u3048\u3066\u3044\u308b\u4ee5\u4e0a\u300c\u52d5\u7684\u30dd\u30ea\u30e2\u30fc\u30d5\u30a3\u30ba\u30e0<\/a>\u300d\u3068\u3057\u3066\u306f\u4f7f\u3048\u307e\u305b\u3093\u3002
    \n\u57fa\u5e95\u30af\u30e9\u30b9\u3078\u306e\u30dd\u30a4\u30f3\u30bf\u306f\u3001\u6d3e\u751f\u30af\u30e9\u30b9\u6bce\u306b\u7570\u306a\u308b\u578b<\/strong>\u306b\u306a\u308b\u305f\u3081\u3001\u540c\u3058\u57fa\u5e95\u30af\u30e9\u30b9\u578b<\/strong>\u306e\u30dd\u30a4\u30f3\u30bf\u3067\u7ba1\u7406\u3067\u304d\u307e\u305b\u3093\u306e\u3067\u3002\uff08\u4f8b\u3048\u3070\uff11\u3064\u306estd::vector\u3067\u300cCTRP\u5f62\u5f0f\u306e\u7570\u306a\u308b\u6d3e\u751f\u30af\u30e9\u30b9\u300d\u306e\u30a4\u30f3\u30b9\u30bf\u30f3\u30b9\u3092\u7ba1\u7406\u51fa\u6765\u306a\u3044\u3068\u3044\u3046\u610f\u5473\u3067\u3059\u3002\u6b21\u306e2.\u3082\u53c2\u7167\u4e0b\u3055\u3044\u3002\uff09<\/p>\n<\/li>\n
  2. \n
    \u300c\u9759\u7684\u30dd\u30ea\u30e2\u30fc\u30d5\u30a3\u30ba\u30e0\u300d\u306e\u3088\u3046\u306b\u3082\u898b\u3048\u307e\u3059\u304c\u3001\u7121\u95a2\u4fc2\u3067\u3059
    \n\u30ef\u30b6\u30ef\u30b6\u6d3e\u751f\u3057\u306a\u304f\u3066\u3082\u3001\u5358\u306b\u540c\u3058\u30b7\u30b0\u30cb\u30c1\u30e3\uff08\u540d\u524d\u3068\u5f15\u6570\u3068\u623b\u308a\u5024\u304c\u540c\u3058\uff09\u95a2\u6570\u3092\u5b9a\u7fa9\u3057\u3066\u304a\u3051\u3070\u3001\u540c\u3058\u8a18\u8ff0\u3067\u547c\u3073\u51fa\u305b\u307e\u3059\u3002<\/p>\n
    \r\n#include <iostream>\r\n#include <vector>\r\nstruct Foo { void print() { std::cout << "This is Foo.\\n"; } };\r\nstruct Bar { void print() { std::cout << "This is Bar.\\n"; } };\r\nint main()\r\n{\r\n    Foo aFoo;\r\n    Bar aBar;\r\n    aFoo.print();\r\n    aBar.print();\r\n\/\/  std::vector<???> aFooBarList;  \/\/ ???\u306b\u4f55\u3092\u66f8\u304f\uff1f\r\n}\r\n<\/pre>\n
    \uff11\u3064\u306e\u30b3\u30f3\u30c6\u30ca\u3067\u7ba1\u7406\u3067\u304d\u306a\u3044\u3068\u3044\u3046\u4e8b\u5b9f\u3082\u5909\u308f\u308a\u307e\u305b\u3093\u3002
    \nFoo\u3068Bar\u304c\u3001\u305d\u308c\u305e\u308cCtrpBase<Foo><\/code>\u3001CtrpBase<Bar><\/code>\u304b\u3089public\u7d99\u627f\u3055\u308c\u3066\u3044\u3066\u3082\u540c\u69d8\u3067\u3059\u3002    \u5b9f\u4f53\u5316<\/a>\u3055\u308c\u3066\u3044\u306a\u3044\u30af\u30e9\u30b9\u30fb\u30c6\u30f3\u30d7\u30ec\u30fc\u30c8\u306f ??? \u306b\u66f8\u3051\u307e\u305b\u3093(*1)<\/code>\u306e\u3067\u3001\u5b9f\u4f53\u5316\u3057\u305fCtrpBase<Foo>*<\/code>\u3001CtrpBase<Bar>*<\/code>\u306e\u3069\u3061\u3089\u304b\u3092\u66f8\u304f\u3057\u304b\u7121\u3044\u3067\u3059\u3002\u66f8\u304b\u306a\u304b\u3063\u305f\u65b9\u306f aFooBarList \u3067\u7ba1\u7406\u3067\u304d\u307e\u305b\u3093\u3002<\/p>\n<\/li>\n<\/ol>\n
    (*1) \u30af\u30e9\u30b9\u30fb\u30c6\u30f3\u30d7\u30ec\u30fc\u30c8\u3092std::vector\u306e\u578b\u3068\u3057\u3066\u6307\u5b9a\u3067\u304d\u306a\u3044<\/strong>
    \n\u30af\u30e9\u30b9\u306f\u300c\u578b\u300d\u3067\u3059\u304c\u3001\u30af\u30e9\u30b9\u30fb\u30c6\u30f3\u30d7\u30ec\u30fc\u30c8\u306f\u96db\u5f62\u3067\u3042\u308a\u300c\u578b\u300d\u3067\u306f\u306a\u3044\u306e\u3067\u3059\u3002std::vector<T>\u306eT\u306b\u306f\u300c\u578b\u300d\u3092\u6307\u5b9a\u3057\u307e\u3059\u304b\u3089\u3001\u30af\u30e9\u30b9\u30fb\u30c6\u30f3\u30d7\u30ec\u30fc\u30c8\u3092\u66f8\u304f\u3053\u3068\u304c\u3067\u304d\u307e\u305b\u3093\u3002
    \n\u56e0\u307f\u306b\u3001\u30c6\u30f3\u30d7\u30ec\u30fc\u30c8\u30fb\u30d1\u30e9\u30e1\u30fc\u30bf\u3068\u3057\u3066\u3001\u4eca\u307e\u3067\u578b\u30d1\u30e9\u30e1\u30fc\u30bf\u3068\u975e\u578b\u30d1\u30e9\u30e1\u30fc\u30bf\u306e\uff12\u7a2e\u985e\u3092\u89e3\u8aac\u3057\u307e\u3057\u305f\u304c\u3001\u4ed6\u306b\u300c\u30c6\u30f3\u30d7\u30ec\u30fc\u30c8\u300d\u30d1\u30e9\u30e1\u30fc\u30bf\u3082\u3042\u308a\u307e\u3059\u3002    \u30c6\u30f3\u30d7\u30ec\u30fc\u30c8\u30fb\u30c6\u30f3\u30d7\u30ec\u30fc\u30c8\u30fb\u30d1\u30e9\u30e1\u30fc\u30bf<\/a>\u3068\u547c\u3070\u308c\u3066\u3044\u307e\u3059\u3002<\/p><\/blockquote>\n
    \uff12\uff0e\u3067\u306f\u3069\u3093\u306a\u6642\u306b\u4fbf\u5229\u306a\u306e\u304b\uff1f<\/h3>\n
    \u4e00\u822c\u306b\u3001\u57fa\u5e95\u30af\u30e9\u30b9\u3067\u30e1\u30f3\u30d0\u5909\u6570\u3084\u30e1\u30f3\u30d0\u95a2\u6570\u3092\u5b9a\u7fa9\u3059\u308b\u3068\u305d\u308c\u3089\u306f\u5168\u3066\u6d3e\u751f\u30af\u30e9\u30b9\u3078\u7d99\u627f\u3055\u308c\u307e\u3059\u3002
    \n\u305d\u3057\u3066\u3001\u901a\u5e38\u306e\u30d1\u30bf\u30fc\u30f3\u3067\u306f\u57fa\u5e95\u30af\u30e9\u30b9\u306f\u6d3e\u751f\u30af\u30e9\u30b9\u306e\u60c5\u5831\u3092\u6301\u3063\u3066\u3044\u306a\u3044\u305f\u3081\u3001\u6d3e\u751f\u30af\u30e9\u30b9\u3078\u306e\u53c2\u7167\u3084\u6d3e\u751f\u30af\u30e9\u30b9\u306e\u30e1\u30f3\u30d0\u95a2\u6570\u547c\u3073\u51fa\u3057\u7b49\u3092\u5b9f\u88c5\u3059\u308b\u3053\u3068\u304c\u3067\u304d\u307e\u305b\u3093\u3002
    \nCRTP\u306f\u3001\u57fa\u5e95\u30af\u30e9\u30b9\u30fb\u30c6\u30f3\u30d7\u30ec\u30fc\u30c8\u306b\u6d3e\u751f\u30af\u30e9\u30b9\u306e\u578b\u3092\u4e0e\u3048\u308b\u3053\u3068\u3067\u305d\u308c\u3089\u3092\u3067\u304d\u308b\u3088\u3046\u306b\u3057\u3066\u3044\u307e\u3059\u3002<\/p>\n
    2-1.\u4f8b\uff11\uff1a\u6bd4\u8f03\u6f14\u7b97\u5b50\u306e\u5c0e\u51fa<\/h4>\n
    2-1-1.\u6bd4\u8f03\u6f14\u7b97\u5b50\u306e\u5c0e\u51fa\u3068\u306f\uff1f<\/h5>\n
    \u6bd4\u8f03\u6f14\u7b97\u5b50\u306f\u304b\u306a\u308a\u305f\u304f\u3055\u3093\u3042\u308a\u307e\u3059\u306d\u3002’==’, ‘!=’, ‘<‘, ‘>’, ‘<=’, ‘>=’
    \n\u305d\u3057\u3066\u3001\u3053\u308c\u3089\u306foperator<<\/code>\u304c\u3042\u308c\u3070\u6b8b\u308a\u3092\u5168\u3066\u8ad6\u7406\u6f14\u7b97\u306e\u307f\u3067\u5c0e\u51fa\u3067\u304d\u307e\u3059\u3002<\/p>\n
    \u4f8b\u3048\u3070\u3001\u7c21\u5358\u306a\u5e74\u6708\u65e5\u306e\u307f\u3092\u8a18\u9332\u3059\u308b\u65e5\u4ed8\u30af\u30e9\u30b9\u3067\u898b\u3066\u307f\u307e\u3057\u3087\u3046\u3002<\/p>\n
    \r\n#include <iostream>\r\n#include <iomanip>\r\n#include <cstdint>\r\n#include <tuple>\r\n\r\nstruct Date\r\n{\r\n    uint16_t    mYear;\r\n    uint8_t     mMonth;\r\n    uint8_t     mDay;\r\n    Date(uint16_t iYear, uint8_t iMonth, uint8_t iDay) :\r\n        mYear(iYear), mMonth(iMonth), mDay(iDay)\r\n    { }\r\n\r\n    bool operator<(Date const& iRhs) const\r\n    {\r\n        return std::tie(mYear, mMonth, mDay) < std::tie(iRhs.mYear, iRhs.mMonth, iRhs.mDay);\r\n    }\r\n\r\n    \/\/ operator<\u304b\u3089\u5c0e\u51fa\r\n    bool operator>(Date  const& iRhs) const { return  (iRhs  < *this); }\r\n    bool operator==(Date const& iRhs) const { return !(*this < iRhs) && !(iRhs < *this); }\r\n    bool operator!=(Date const& iRhs) const { return  (*this < iRhs) ||  (iRhs < *this); }\r\n    bool operator<=(Date const& iRhs) const { return !(iRhs  < *this); }\r\n    bool operator>=(Date const& iRhs) const { return !(*this < iRhs); }\r\n};\r\n\r\nint main()\r\n{\r\n    Date aToday(2018, 2, 18);\r\n    Date aTomorrow(2018, 2, 19);\r\n\r\n    std::cout << std::boolalpha;\r\n    std::cout << "aToday <  aTomorrow = " << (aToday < aTomorrow) << "  : ";\r\n    std::cout << "aToday <  aToday = "    << (aToday < aToday) << "\\n";\r\n\r\n    std::cout << "aToday >  aTomorrow = " << (aToday > aTomorrow) << " : ";\r\n    std::cout << "aToday >  aToday = "    << (aToday > aToday) << "\\n";\r\n    \/\/ \u4ee5\u4e0b\u7565\r\n}\r\n<\/pre>\n
    \r\naToday <  aTomorrow = true  : aToday <  aToday = false\r\naToday >  aTomorrow = false : aToday >  aToday = false\r\naToday == aTomorrow = false : aToday == aToday = true\r\naToday != aTomorrow = true  : aToday != aToday = false\r\naToday <= aTomorrow = true  : aToday <= aToday = true\r\naToday >= aTomorrow = false : aToday >= aToday = true\r\n<\/pre>\n
    Wandbox\u3067\u78ba\u8a8d\u3059\u308b\u3002<\/a><\/p>\n
    \u3042\u308b\u6642\u3001\u5927\u5c0f\u6bd4\u8f03\u3092\u6587\u5b57\u5217\u306e\u9577\u3055\u3067\u5b9a\u7fa9\u3057\u305f\u3044\u30b1\u30fc\u30b9\u304c\u767a\u751f\u3057\u305f\u306e\u3067\u6b21\u306e\u5b9a\u7fa9\u3092\u4f5c\u308a\u307e\u3057\u305f\u3002<\/p>\n
    \r\nstruct SizeString : public std::string\r\n{\r\n    using std::string::string;\r\n\r\n    bool operator<(SizeString const& iRhs) const\r\n    {\r\n        return size() < iRhs.size();\r\n    }\r\n\r\n    \/\/ operator<\u304b\u3089\u5c0e\u51fa\r\n    bool operator>(SizeString   const& iRhs) const { return  (iRhs  < *this); }\r\n    bool operator==(SizeString  const& iRhs) const { return !(*this < iRhs) && !(iRhs < *this); }\r\n    bool operator!=(SizeString  const& iRhs) const { return  (*this < iRhs) ||  (iRhs < *this); }\r\n    bool operator<=(SizeString  const& iRhs) const { return !(iRhs  < *this); }\r\n    bool operator>=(SizeString  const& iRhs) const { return !(*this < iRhs); }\r\n};\r\n<\/pre>\n
    2-1-2.\u6bd4\u8f03\u6f14\u7b97\u5b50\u306e\u5c0e\u51fa\u306bCRTP\u3092\u4f7f\u3046<\/h5>\n
    \u4ed6\u306e\u6bd4\u8f03\u6f14\u7b97\u5b50\u3082\u5fc5\u8981\u306a\u5834\u5408\u3001\u6b8b\u308a\u306e\u6bd4\u8f03\u6f14\u7b97\u5b50\u3092\u5168\u3066\u30b3\u30d4\u30da\u3057\u3066\u30d1\u30e9\u30e1\u30fc\u30bf\u306e\u578b\u304c\u7570\u306a\u308b\u306e\u3067\uff11\u3064\uff11\u3064\u4fee\u6b63\u3057\u307e\u3059\u3002\u306a\u304b\u306a\u304b\u9762\u5012\u3067\u3059\u306d\u3002\u305d\u306e\u3088\u3046\u306a\u6642\u3001CRTP\u306e\u51fa\u756a\u3067\u3059\u3002<\/p>\n
    \u307e\u305a\u306f\u6b21\u306e\u3088\u3046\u306a\u5c0e\u51fa\u3059\u308b\u6bd4\u8f03\u6f14\u7b97\u5b50\u3060\u3051\u3092\u5b9a\u7fa9\u3057\u305f\u30af\u30e9\u30b9\u30fb\u30c6\u30f3\u30d7\u30ec\u30fc\u30c8\u3092\u5b9a\u7fa9\u3057\u307e\u3059\u3002
    \n\u305d\u306e\u6642\u3001\u6d3e\u751f\u30af\u30e9\u30b9\u3092\u30d1\u30e9\u30e1\u30fc\u30bf\u306b\u53d6\u308b\u3053\u3068\u3067\u3001<\/strong>\u6d3e\u751f\u30af\u30e9\u30b9\u306eoperator<<\/code>\u3092\u547c\u3073\u51fa\u3055\u305b\u307e\u3059\u3002<\/strong>
    \n\u3053\u306e\u3088\u3046\u306b\u57fa\u5e95\u30af\u30e9\u30b9\u304b\u3089\u6d3e\u751f\u30af\u30e9\u30b9\u306e\u30e1\u30f3\u30d0\u95a2\u6570\u3092\u76f4\u63a5<\/strong>\u547c\u3073\u51fa\u305b\u308b\u3053\u3068\u304cCRTP\u306e\u7279\u9577\u306e\uff11\u3064\u3067\u3059\u3002<\/p>\n
    \r\ntemplate<class tDerived>\r\nstruct CompareBase\r\n{\r\n    \/\/ operator<\u304b\u3089\u5c0e\u51fa\r\n    bool operator>(tDerived const& iRhs)  const\r\n    {\r\n        return  (iRhs  < static_cast<tDerived const&>(*this));\r\n    }\r\n    bool operator==(tDerived const& iRhs) const\r\n    {\r\n        return !(static_cast<tDerived const&>(*this) < iRhs)\r\n            && !(iRhs < static_cast<tDerived const&>(*this));\r\n    }\r\n    bool operator!=(tDerived const& iRhs) const\r\n    {\r\n        return  (static_cast<tDerived const&>(*this) < iRhs)\r\n            ||  (iRhs < static_cast<tDerived const&>(*this));\r\n    }\r\n    bool operator<=(tDerived const& iRhs) const\r\n    {\r\n        return !(iRhs  < static_cast<tDerived const&>(*this));\r\n    }\r\n    bool operator>=(tDerived const& iRhs) const\r\n    {\r\n        return !(static_cast<tDerived const&>(*this) < iRhs);\r\n    }\r\n};\r\n<\/pre>\n
    \u6bd4\u8f03\u6f14\u7b97\u5b50\u3092\u81ea\u52d5\u7684\u306b\u5c0e\u51fa\u3057\u305f\u3044\u30af\u30e9\u30b9\u306b\u3064\u3044\u3066\u3001\u6b21\u306e\u3088\u3046\u306b\u4f7f\u3044\u307e\u3059\u3002<\/p>\n
    \r\nstruct Date : public CompareBase<Date>\r\n{\r\n    uint16_t    mYear;\r\n    uint8_t     mMonth;\r\n    uint8_t     mDay;\r\n    Date(uint16_t iYear, uint8_t iMonth, uint8_t iDay) :\r\n        mYear(iYear), mMonth(iMonth), mDay(iDay)\r\n    { }\r\n\r\n    bool operator<(Date const& iRhs) const\r\n    {\r\n        return std::tie(mYear, mMonth, mDay) < std::tie(iRhs.mYear, iRhs.mMonth, iRhs.mDay);\r\n    }\r\n};\r\n\r\nstruct SizeString : public std::string, public CompareBase<SizeString>\r\n{\r\n    using std::string::string;\r\n\r\n    bool operator<(SizeString const& iRhs) const\r\n    {\r\n        return size() < iRhs.size();\r\n    }\r\n};\r\n<\/pre>\n
    \u305f\u3044\u3078\u3093\u304a\u624b\u8efd\u306b\u8907\u6570\u306e\u30af\u30e9\u30b9\u3067\u6bd4\u8f03\u6f14\u7b97\u5b50\u7fa4\u3092\u5b9f\u88c5\u3067\u304d\u307e\u3057\u305f\u3002<\/p>\n
    Wandbox\u3067\u78ba\u8a8d\u3059\u308b\u3002<\/a><\/p>\n
    \u30c0\u30a6\u30f3\u30ad\u30e3\u30b9\u30c8\u306b\u3064\u3044\u3066<\/strong>
    \nstatic_cast\u3092\u4f7f\u3063\u3066\u30c0\u30a6\u30f3\u30ad\u30e3\u30b9\u30c8\u3057\u3066\u3044\u307e\u3059\u3002\u9069\u5207\u306bCRTP\u306b\u5f93\u3063\u3066\u3044\u308c\u3070static_cast\u3067\u554f\u984c\u3042\u308a\u307e\u305b\u3093\u304c\u3001\u4f7f\u3044\u65b9\u3092\u8aa4\u308b\u3068    \u5371\u967a\u306astatic_cast<\/a>\u306b\u306a\u308a\u307e\u3059\u3002\u5fc3\u914d\u306a\u5834\u5408\u306fdynamic_cast<\/a>\u3059\u308b\u3053\u3068\u3082\u53ef\u80fd\u3067\u3059\u3002\u305d\u306e\u5834\u5408\u306f\u3001\u5f97\u5931\u3092\u691c\u8a0e\u3057\u305f\u4e0a\u3067\u4eee\u60f3\u95a2\u6570\u3082\u8a2d\u3051\u3066\u4e0b\u3055\u3044\u3002<\/p><\/blockquote>\n
    2-2.\u4eee\u60f3\u95a2\u6570\u3092\u7528\u3044\u308b\u5834\u5408\u3068\u306e\u6bd4\u8f03<\/h4>\n
    \u300c\u57fa\u5e95\u30af\u30e9\u30b9\u304b\u3089\u6d3e\u751f\u30af\u30e9\u30b9\u306e\u30e1\u30f3\u30d0\u95a2\u6570\u3092\u547c\u3073\u51fa\u3059\u300d\u3068\u8a00\u3048\u3070\u3001\u4eee\u60f3\u95a2\u6570\u3067\u3059\u306d\u3002
    \n\u5b9f\u969b\u3001\u540c\u69d8\u306a\u3053\u3068\u3092\u4eee\u60f3\u95a2\u6570\u3092\u7528\u3044\u3066\u5b9f\u73fe\u3067\u304d\u307e\u3059\u3002<\/p>\n
      \n
    1. CompareBase\u3092\u901a\u5e38\u306e\u30af\u30e9\u30b9\u3068\u3059\u308b<\/li>\n
    2. CompareBase\u306eoperator<\u3092\u7d14\u7c8b\u4eee\u60f3\u95a2\u6570\u3068\u3057\u3066\u5b9a\u7fa9\u3059\u308b<\/li>\n
    3. \u6d3e\u751f\u30af\u30e9\u30b9\u3001\u57fa\u5e95\u30af\u30e9\u30b9\u306e\u4e21\u65b9\u306e\u6bd4\u8f03\u6f14\u7b97\u5b50\u306e\u30d1\u30e9\u30e1\u30fc\u30bf\u3092\u57fa\u5e95\u30af\u30e9\u30b9\u3067\u53d7\u3051\u53d6\u308b<\/li>\n
    4. \u6d3e\u751f\u30af\u30e9\u30b9\u306eoperator<\u306f\u30d1\u30e9\u30e1\u30fc\u30bf\u3092\u6d3e\u751f\u30af\u30e9\u30b9\u3078static_cast\u3057\u3066\u51e6\u7406\u3059\u308b
      \n\u3053\u3053\u306fdynamic_cast\u306e\u5fc5\u8981\u306f\u307e\u305a\u306a\u3044\u3068\u601d\u3044\u307e\u3059\u3002\u81ea\u5206\u306e\u57fa\u5e95\u30af\u30e9\u30b9\u3092\u30d1\u30e9\u30e1\u30fc\u30bf\u306b\u6307\u5b9a\u3059\u308b\u306e\u3067\u3059\u304b\u3089\u3001\u30c0\u30a6\u30f3\u30ad\u30e3\u30b9\u30c8\u53ef\u80fd\u3067\u3059\u3002\u3057\u304b\u3057\u3001\u30d1\u30e9\u30e1\u30fc\u30bf\u306e\u578b\u3092\u9593\u9055\u3046\u3068      \u5371\u967a\u306astatic_cast<\/a>\u306b\u306a\u308b\u306e\u3067\u3001\u305d\u306e\u30d0\u30b0\u3092\u78ba\u5b9f\u306b\u691c\u51fa\u3057\u305f\u3044\u5834\u5408\u306fdynamic_cast<\/a>\u3092\u4f7f\u3046\u306e\u3082\u6709\u308a\u3068\u601d\u3044\u307e\u3059\u3002<\/li>\n<\/ol>\n
      \r\nstruct CompareBase\r\n{\r\n    virtual bool operator<(CompareBase const& iRhs)  const = 0;\r\n\r\n    \/\/ operator<\u304b\u3089\u5c0e\u51fa\r\n    bool operator>(CompareBase const& iRhs)  const { return  (iRhs  < *this); }\r\n    bool operator==(CompareBase const& iRhs) const { return !(*this < iRhs) && !(iRhs < *this); }\r\n    bool operator!=(CompareBase const& iRhs) const { return  (*this < iRhs) ||  (iRhs < *this); }\r\n    bool operator<=(CompareBase const& iRhs) const { return !(iRhs  < *this); }\r\n    bool operator>=(CompareBase const& iRhs) const { return !(*this < iRhs); }\r\n};\r\n\r\nstruct Date : public CompareBase\r\n{\r\n    uint16_t    mYear;\r\n    uint8_t     mMonth;\r\n    uint8_t     mDay;\r\n    Date(uint16_t iYear, uint8_t iMonth, uint8_t iDay) :\r\n        mYear(iYear), mMonth(iMonth), mDay(iDay)\r\n    { }\r\n\r\n    bool operator<(CompareBase const& iRhs) const\r\n    {\r\n        auto aRhs = static_cast<Date const&>(iRhs);\r\n        return std::tie(mYear, mMonth, mDay) < std::tie(aRhs.mYear, aRhs.mMonth, aRhs.mDay);\r\n    }\r\n};\r\n\r\nstruct SizeString : public std::string, public CompareBase\r\n{\r\n    using std::string::string;\r\n\r\n    bool operator<(CompareBase const& iRhs) const\r\n    {\r\n        auto aRhs = static_cast<SizeString const&>(iRhs);\r\n        return size() < aRhs.size();\r\n    }\r\n};\r\n<\/pre>\n
      Wandbox\u3067\u78ba\u8a8d\u3059\u308b\u3002<\/a><\/p>\n
      \u540c\u3058\u3053\u3068\u304c\u3067\u304d\u308b\u306e\u3067\u3042\u308c\u3070\u3001\u3069\u3061\u3089\u3092\u4f7f\u3063\u305f\u65b9\u304c\u826f\u3044\u304b\u60a9\u307f\u307e\u3059\u306d\u3002\u5b9f\u969b\u3001\u4e00\u9577\u4e00\u77ed\u304c\u3042\u308b\u306e\u3067\u3053\u3053\u306f\u60a9\u307f\u3069\u3053\u308d\u3067\u3059\u3002<\/p>\n
        \n
      1. \u4eee\u60f3\u95a2\u6570\u306e\u30e1\u30ea\u30c3\u30c8
        \n\u5fc5\u8981\u306a\u5834\u5408\u306b\u306f\u52d5\u7684\u30dd\u30ea\u30e2\u30fc\u30d5\u30a3\u30ba\u30e0\u3092\u4f7f\u3048\u307e\u3059\u3002\u57fa\u5e95\u30af\u30e9\u30b9\u3078\u306e\u30dd\u30a4\u30f3\u30bf\u3092\u4ecb\u3057\u3066\u3001\u5168\u3066\u306e\u6bd4\u8f03\u6f14\u7b97\u5b50\u3092\u4f7f\u3048\u307e\u3059\u3002
        \n\u9006\u306bCRTP\u3067\u306f\u305d\u308c\u306f\u3067\u304d\u307e\u305b\u3093\u3002<\/p>\n<\/li>\n
      2. \n
        \u4eee\u60f3\u95a2\u6570\u306e\u30c7\u30e1\u30ea\u30c3\u30c8
        \n\u2460 \u4eee\u60f3\u95a2\u6570\u30c6\u30fc\u30d6\u30eb(vtable)\u7d4c\u7531\u3067\u6d3e\u751f\u30af\u30e9\u30b9\u306eoperator<<\/code>\u3092\u547c\u3073\u51fa\u3057\u307e\u3059\u306e\u3067\u5fae\u5999\u306b\u9045\u3044\u3067\u3059\u3002\u3053\u308c\u306f\u30b8\u30e3\u30f3\u30d7\u5148\u306e\u53d6\u5f97\u306b\uff11\u30af\u30c3\u30b7\u30e7\u30f3\u5165\u308b\u3060\u3051\u3067\u3059\u306e\u3067\u3001\u3053\u308c\u3060\u3051\u306a\u3089\u5927\u304d\u304f\u306f\u52a3\u5316\u3057\u306a\u3044\u7b48\u3067\u3059\u3002
        \n\u2461 \u3057\u304b\u3057\u3001\u4eee\u60f3\u95a2\u6570\u30c6\u30fc\u30d6\u30eb\u3092\u7d4c\u7531\u3059\u308b\u306e\u3067\u30a4\u30f3\u30e9\u30a4\u30f3\u5c55\u958b\u3055\u308c\u307e\u305b\u3093\u3002\u30a4\u30f3\u30e9\u30a4\u30f3\u5c55\u958b\u3055\u308c\u306a\u3044\u3068\u3044\u3046\u3053\u3068\u306f\u6700\u9069\u5316\u3082\u52a3\u5316\u3057\u307e\u3059\u3002\u4eca\u56de\u306e\u3088\u3046\u306b\u975e\u5e38\u306b\u77ed\u3044\u95a2\u6570\u306e\u5834\u5408\u3001\u610f\u5916\u306b\u5927\u304d\u304f\u6027\u80fd\u304c\u843d\u3061\u308b\u5834\u5408\u3082\u3042\u308b\u3068\u601d\u3044\u307e\u3059\u3002<\/p>\n<\/li>\n<\/ol>\n
        \u5f93\u3063\u3066\u3001\u52d5\u7684\u30dd\u30ea\u30e2\u30fc\u30d5\u30a3\u30ba\u30e0\u3092\u4f7f\u3046\u5fc5\u8981\u304c\u306a\u3044\u6642\u306fCRTP\u3092\u4f7f\u3063\u305f\u65b9\u304c\u597d\u307e\u3057\u3044\u3067\u3059\u3002
        \n\u4e0a\u8a18\u306e\u30b5\u30f3\u30d7\u30eb\u306e\u3088\u3046\u306aDate\u30af\u30e9\u30b9\u3068SizeString\u30af\u30e9\u30b9\u3092\u30dd\u30ea\u30e2\u30fc\u30d5\u30a3\u30c3\u30af\u306b\u7ba1\u7406\u3059\u308b\u30b1\u30fc\u30b9\u306f\u5c11\u306a\u3044\u3067\u3057\u3087\u3046\u304b\u3089\u3001\u3053\u306e\u72b6\u6cc1\u3082\u5c11\u306a\u304f\u306a\u3044\u3068\u601d\u3044\u307e\u3059\u3002<\/p>\n
        2-3.\u4f8b\uff12\uff1a\u30b7\u30f3\u30b0\u30eb\u30c8\u30f3\u306e\u91cf\u7523<\/h4>\n
        \u5148\u306e\u4f8b\u3067\u306f\u3001\u57fa\u5e95\u30af\u30e9\u30b9\u304b\u3089\u6d3e\u751f\u30af\u30e9\u30b9\u306e\u30e1\u30f3\u30d0\u95a2\u6570\u3092\u547c\u3073\u51fa\u3057\u307e\u3057\u305f\u3002
        \n\u57fa\u5e95\u30af\u30e9\u30b9\u306b\u6d3e\u751f\u30af\u30e9\u30b9\u3078\u306e\u53c2\u7167\u30e1\u30f3\u30d0\u3092\u5b9a\u7fa9\u3059\u308b\u3053\u3068\u3082\u3067\u304d\u307e\u3059\u3002\u305d\u306e\u4f8b\u3068\u3057\u3066\u30b7\u30f3\u30b0\u30eb\u30c8\u30f3\u3092\u53d6\u308a\u4e0a\u3052\u3066\u307f\u307e\u3059\u3002
        \n\u3053\u306e\u4f8b\u3067\u306fstatic\u30e1\u30f3\u30d0\u5909\u6570\u3092\u5b9a\u7fa9\u3057\u307e\u3059\u304c\u3001\u975estatic\u30e1\u30f3\u30d0\u5909\u6570\u3082\u53ef\u80fd\u3067\u3059\u3002<\/p>\n
        \u30b7\u30f3\u30b0\u30eb\u30c8\u30f3\u3068\u306f<\/strong>
        \n\u30b7\u30f3\u30b0\u30eb\u30c8\u30f3\u306f\u30a4\u30f3\u30b9\u30bf\u30f3\u30b9\u304c\uff11\u3064\u3057\u304b\u4f5c\u308c\u306a\u3044\u3088\u3046\u306b\u5236\u9650\u3055\u308c\u305f\u30af\u30e9\u30b9\u3067\u3059\u3002
        \n\u3064\u307e\u308a\u3001\u666e\u901a\u306e\u30af\u30e9\u30b9\u306e\u65b9\u304c\u6a5f\u80fd\u306f\u8c4a\u5bcc\uff08\u8907\u6570\u306e\u30a4\u30f3\u30b9\u30bf\u30f3\u30b9\u3092\u4f5c\u308c\u308b\uff09\u3067\u3059\u306e\u3067\u3001\u901a\u5e38\u306e\u30af\u30e9\u30b9\u3067\u3082\u8db3\u308a\u307e\u3059\u304c\u3001\u30a4\u30f3\u30b9\u30bf\u30f3\u30b9\u3092\uff11\u3064\u3057\u304b\u4f5c\u308a\u305f\u304f\u306a\u3044\u5834\u5408\u3082\u3042\u308a\u307e\u3059\u3002
        \n\u4f8b\u3048\u3070\u3001\u30c8\u30e9\u30d6\u30eb\u8ffd\u8de1\u7528\u306e\u30ed\u30b0\u51fa\u529b\u30af\u30e9\u30b9\u306e\u30a4\u30f3\u30b9\u30bf\u30f3\u30b9\u306f\u30d7\u30ed\u30b0\u30e9\u30e0\u5185\u306b\uff11\u3064\u3060\u3051\u5b58\u5728\u3055\u305b\u305f\u3044\u5834\u5408\u3082\u3042\u308a\u307e\u3059\u3002\u3057\u304b\u3057\u3001C++\u306e\u30c7\u30d5\u30a9\u30eb\u30c8\u52d5\u4f5c\u306f\u30b3\u30d4\u30fc\u3067\u3059\u306e\u3067\u6cb9\u65ad\u3084\u898b\u843d\u3068\u3057\u3067\u30b3\u30d4\u30fc\u306b\u306a\u308b\u53ef\u80fd\u6027\u3082\u7121\u8996\u3067\u304d\u307e\u305b\u3093\u3002\u305d\u306e\u3061\u3087\u3063\u3068\u3057\u305f\u6cb9\u65ad\u3067\u30ed\u30b0\u7528\u30a4\u30f3\u30b9\u30bf\u30f3\u30b9\u304c\u8907\u6570\u751f\u6210\u3055\u308c\u308b\u3068\u30ed\u30b0\u304c\u6b63\u5e38\u306b\u3068\u308c\u306a\u304f\u306a\u308a\u307e\u3059\u3002\u30c8\u30e9\u30d6\u30eb\u8ffd\u8de1\u7528\u306e\u30ed\u30b0\u81ea\u4f53\u304c\u30c8\u30e9\u30d6\u30eb\u3067\u53ef\u7b11\u3057\u304f\u306a\u308b\u3068\u306f\u76ee\u3082\u5f53\u3066\u3089\u308c\u307e\u305b\u3093\u3002
        \n\u305d\u306e\u3088\u3046\u306a\u5834\u5408\u306f\u30b7\u30f3\u30b0\u30eb\u30c8\u30f3\u3068\u3057\u3001\u81ea\u5206\u3082\u542b\u3081\u3066\u8ab0\u304b\u304c\u9593\u9055\u3063\u3066\u30b3\u30d4\u30fc\u3057\u305f\u3089\u30b3\u30f3\u30d1\u30a4\u30eb\u30a8\u30e9\u30fc\u306b\u306a\u308b\u3088\u3046\u306b\u4ed5\u8fbc\u3093\u3067\u304a\u304f\u3068\u5b89\u5fc3\u3067\u3059\u3002<\/p><\/blockquote>\n
        2-3-1.\u7c21\u5358\u306a\u30b7\u30f3\u30b0\u30eb\u30c8\u30f3<\/h5>\n
        \u30b7\u30f3\u30b0\u30eb\u30c8\u30f3\u306e\u4f5c\u308a\u65b9\u306f\u3044\u304f\u3064\u304b\u3042\u308a\u307e\u3059\u304c\u3001\u3053\u3053\u3067\u306f\u6b21\u306e\u65b9\u6cd5\u3067\u4f5c\u308a\u307e\u3059\u3002<\/p>\n
          \n
        1. \u552f\u4e00\u306e\u30a4\u30f3\u30b9\u30bf\u30f3\u30b9\u3092getInstance()\u95a2\u6570\u306estatic\u30ed\u30fc\u30ab\u30eb\u5909\u6570\u3068\u3057\u3066\u7372\u5f97\u3059\u308b\u3002<\/li>\n
        2. \u30a4\u30f3\u30b9\u30bf\u30f3\u30b9\u3092\u5897\u3084\u3059\u30e1\u30f3\u30d0\u95a2\u6570\u306fprivate\u5b9a\u7fa9\u3057\u305f\u308a\u3001delete\u3057\u305f\u308a\u3059\u308b\u3002<\/li>\n
        3. \u30a2\u30d7\u30ea\u8d77\u52d5\u6642\u306b\u30a4\u30f3\u30b9\u30bf\u30f3\u30b9\u3092\u81ea\u52d5\u751f\u6210\u3059\u308b\u3002
          \n\u3053\u306e3.\u306f\u304a\u52e7\u3081\u30aa\u30d7\u30b7\u30e7\u30f3\u3067\u3059\u3002<\/p>\n