22.9.2.2 Constructors [bitset.cons] C++N4910:2022 (609) p734.cpp

# はじめに(Introduction)

N4910  Working Draft, Standard for Programming Language C++

http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2022/n4910.pdf

n4910は、ISO/IEC JTC1 SC22 WG21の作業原案(Working Draft)です。
公式のISO/IEC 14882原本ではありません。
ISO/IEC JTC1 SC22 WG21では、可能な限り作業文書を公開し、幅広い意見を求めています。
一連の記事はコード断片をコンパイルできる形にする方法を検討してコンパイル、リンク、実行して、規格案の原文と処理系(g++, Clang++)との違いを確認し、技術内容を検討し、ISO/IEC JTC1 SC22 WG21にフィードバックするために用います。
また、CERT C++, MISRA C++等のコーディング標準のコード断片をコンパイルする際の参考にさせていただこうと考えています。CERT C++, MISRA C++が標準化の動きとの時間的なずれがあれば確認できれば幸いです。また、boostライブラリとの関連、Linux OS, TOPPERSカーネル、g++(GCC), clang++(LLVM）との関係も調査中です。
何か、抜け漏れ、耳より情報がありましたらおしらせくださると幸いです。

 <この項は書きかけです。順次追記します。>

## 背景(back ground)
C/C++でコンパイルエラーが出ると、途方にくれることがしばしばあります。
何回かに１回は、該当するエラーが検索できます。
ただ、条件が違っていて、そこでの修正方法では目的を達成しないこともしばしばです。いろいろな条件のコンパイルエラーとその対応方法について、広く記録することによって、いつか同じエラーに遭遇した時にやくに立つことを目指しています。

この半年の間で、三度、自分のネットでの記録に助けられたことがあります。
また過去に解決できなかった記録を１０種類以上、最近になって解決できたことがあります。それは、主に次の３つの情報に基づいています。

https://stackoverflow.com

http://ja.cppreference.com/

cpprefjp - C++日本語リファレンス

https://cpprefjp.github.io/

コンパイラの実装状況

https://cpprefjp.github.io/implementation-status.html

また
https://researchmap.jp/joub9b3my-1797580/#_1797580
に記載したサイトのお世話になっています。

## 作業方針(sequence)
Clang++では-std=c++03, C++2bの2種類
g++では-std=c++03, c++2bの２種類
でコンパイルし、

１）コンパイルエラーを収集する。
２）コンパイルエラーをなくす方法を検討する。
コンパイルエラーになる例を示すだけが目的のコードは、コンパイルエラーをなくすのではなく、コンパイルエラーの種類を収集するだけにする。
文法を示すのが目的のコード場合に、コンパイルエラーをなくすのに手間がかかる場合は、順次作業します。
３）リンクエラーをなくす方法を検討する。
文法を示すのが目的のコード場合に、リンクエラーをなくすのに手間がかかる場合は、順次作業します。
４）意味のある出力を作る。
コンパイル、リンクが通っても、意味のある出力を示そうとすると、コンパイル・リンクエラーが出て収拾できそうにない場合がある。順次作業します。

１）だけのものから４）まで進んだものと色々ある状態です。一歩でも前に進むご助言をお待ちしています。「検討事項」の欄に現状を記録するようにしています。

### C++N4910:2022 Standard Working Draft on ISO/IEC 14882(0) sample code compile list  

https://qiita.com/kaizen_nagoya/items/fc957ddddd402004bb91

### C++N4741, 2018 Standard Working Draft on ISO/IEC 14882 sample code compile list
https://qiita.com/kaizen_nagoya/items/3294c014044550896010

### C++N4606, 2016符号断片編纂一覧(example code compile list)
C++N4606, 2016 Working Draft 2016, ISO/IEC 14882, C++ standard(1) Example code compile list
https://qiita.com/kaizen_nagoya/items/df5d62c35bd6ed1c3d43/

### C++N3242, 2011 sample code compile list on clang++ and g++
https://qiita.com/kaizen_nagoya/items/685b5c1a2c17c1bf1318

## 編纂器(Compiler)
### clang++ --version
> Debian clang version 14.0.5-++20220610033153+c12386ae247c-1~exp1~20220610153237.151
Target: x86_64-pc-linux-gnu, Thread model: posix, InstalledDir: /usr/bin

### g++- --version
> g++ (GCC) 12.1.0  Copyright (C) 2022 Free Software Foundation, Inc.
This is free software; see the source for copying conditions. There is NO
warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.

# 22.9.2.2 Constructors [bitset.cons] C++N4910:2022 (609) p734.cpp

## 算譜(source code)

```c++:p734.cpp
// C++N4910 Committee Draft, Standard for Programming Language C++
// http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2022/n4910.pdf
const char * n4910 = "22.9.2.2 Constructors [bitset.cons] C++N4910:2022 (609) p734.cpp";
// Debian clang version 14.0.5-++20220610033153+c12386ae247c-
// g++ (GCC) 12.1.0 Copyright (C) 2022 Free Software Foundation, Inc.
// Edited by Dr. OGAWA Kiyoshi. Compile procedure and results record.
// C++N4910:2022 Standard Working Draft on ISO/IEC 14882(0) sample code compile list
// https://qiita.com/kaizen_nagoya/items/fc957ddddd402004bb91

#include "N4910.h"

using namespace std;

// Example 1  
constexpr bitset() noexcept;
// Effects: Initializes all bits in *this to zero.
constexpr bitset(unsigned long long val) noexcept;
// Effects: Initializes the first M bit positions to the corresponding bit values in val. M is the smaller of N and the number of bits in the value representation (6.8.1) of unsigned long long. If M < N, the remaining bit positions are initialized to zero.
template<class charT, class traits, class Allocator>
  explicit bitset(
const basic_string<charT, traits, Allocator>& str,
typename basic_string<charT, traits, Allocator>::size_type pos = 0,
typename basic_string<charT, traits, Allocator>::size_type n
  = basic_string<charT, traits, Allocator>::npos,
charT zero = charT(’0’),
charT one = charT(’1’));
// Effects: Determines the effective length rlen of the initializing string as the smaller of n and str.size() - pos. Initializes the first M bit positions to values determined from the corresponding characters in the
string str. M is the smaller of N and rlen.
// An element of the constructed object has value zero if the corresponding character in str, beginning at position pos, is zero. Otherwise, the element has the value one. Character position pos + M - 1 corresponds to bit position zero. Subsequent decreasing character positions correspond to increasing bit positions.
// If M < N, remaining bit positions are initialized to zero.
The function uses traits::eq to compare the character values.
// Throws: out_of_range if pos > str.size() or invalid_argument if any of the rlen characters in str beginning at position pos is other than zero or one.
// 22.9.3, hash support
template<class T> struct hash; template<size_t N> struct hash<bitset<N>>;
}
//  The class template bitset<N> describes an object that can store a sequence consisting of a fixed number of bits, N.
//  Each bit represents either the value zero (reset) or one (set). To toggle a bit is to change the value zero to one, or the value one to zero. Each bit has a non-negative position pos. When converting between an object of class bitset<N> and a value of some integral type, bit position pos corresponds to the bit value 1 << pos. The integral value corresponding to two or more bits is the sum of their bit values.
// associated with a distinct exception:
constexpr bitset() noexcept;
Effects: Initializes all bits in *this to zero. constexpr bitset(unsigned long long val) noexcept;
// Effects: Initializes the first M bit positions to the corresponding bit values in val. M is the smaller of N and the number of bits in the value representation (6.8.1) of unsigned long long. If M < N, the remaining bit positions are initialized to zero.
template<class charT, class traits, class Allocator>
  explicit bitset(
template<class charT>
  explicit bitset(
const charT* str,
typename basic_string<charT>::size_type n = basic_string<charT>::npos,
charT zero = charT(’0’),
charT one = charT(’1’));
// Effects: As if by:
   bitset(n == basic_string<charT>::npos
             ? basic_string<charT>(str)
             : basic_string<charT>(str, n),
          0, n, zero, one)
int main(){
  cout  <<  n4910 << endl;
  return EXIT_SUCCESS;
}
```

## 編纂・実行結果(compile and go)

```ubuntu:bash
$ clang++ p734.cpp -std=03 -o p734l -I. -Wall
In file included from p734.cpp:10:
In file included from ./N4910.h:10:
In file included from /usr/bin/../lib/gcc/x86_64-linux-gnu/10/../../../../include/c++/10/atomic:38:
/usr/bin/../lib/gcc/x86_64-linux-gnu/10/../../../../include/c++/10/bits/c++0x_warning.h:32:2: error: This file requires compiler and library support for the ISO C++ 2011 standard. This support must be enabled with the -std=c++11 or -std=gnu++11 compiler options.
#error This file requires compiler and library support \
 ^
p734.cpp:15:1: error: unknown type name 'constexpr'
constexpr bitset() noexcept;
^
p734.cpp:15:20: error: expected function body after function declarator
constexpr bitset() noexcept;
                   ^
p734.cpp:17:1: error: unknown type name 'constexpr'
constexpr bitset(unsigned long long val) noexcept;
^
p734.cpp:17:42: error: expected function body after function declarator
constexpr bitset(unsigned long long val) noexcept;
                                         ^
p734.cpp:25:20: error: unexpected character <U+2019>
charT zero = charT(’0’),
                   ^
p734.cpp:25:24: error: character <U+2019> not allowed in an identifier
charT zero = charT(’0’),
                     ^
p734.cpp:25:24: error: invalid suffix '’' on integer constant
p734.cpp:26:19: error: unexpected character <U+2019>
charT one = charT(’1’));
                  ^
p734.cpp:26:23: error: character <U+2019> not allowed in an identifier
charT one = charT(’1’));
                    ^
p734.cpp:26:23: error: invalid suffix '’' on integer constant
p734.cpp:20:12: error: C++ requires a type specifier for all declarations
  explicit bitset(
  ~~~~~~~~ ^
p734.cpp:32:73: error: expected expression
template<class T> struct hash; template<size_t N> struct hash<bitset<N>>;
                                                                        ^
p734.cpp:32:73: error: expected '>'
p734.cpp:32:69: note: to match this '<'
template<class T> struct hash; template<size_t N> struct hash<bitset<N>>;
                                                                    ^
p734.cpp:32:73: error: expected a type
template<class T> struct hash; template<size_t N> struct hash<bitset<N>>;
                                                                        ^
p734.cpp:32:73: error: expected '>'
p734.cpp:32:62: note: to match this '<'
template<class T> struct hash; template<size_t N> struct hash<bitset<N>>;
                                                             ^
p734.cpp:33:1: error: extraneous closing brace ('}')
}
^
p734.cpp:37:1: error: unknown type name 'constexpr'
constexpr bitset() noexcept;
^
p734.cpp:37:20: error: expected function body after function declarator
constexpr bitset() noexcept;
                   ^
fatal error: too many errors emitted, stopping now [-ferror-limit=]
20 errors generated.
$ clang++ p734.cpp -std=2b -o p734l -I. -Wall
p734.cpp:15:11: error: C++ requires a type specifier for all declarations
constexpr bitset() noexcept;
~~~~~~~~~ ^
p734.cpp:17:11: error: C++ requires a type specifier for all declarations
constexpr bitset(unsigned long long val) noexcept;
~~~~~~~~~ ^
p734.cpp:25:20: error: unexpected character <U+2019>
charT zero = charT(’0’),
                   ^
p734.cpp:25:24: error: character <U+2019> not allowed in an identifier
charT zero = charT(’0’),
                     ^
p734.cpp:25:24: error: invalid suffix '’' on integer constant
p734.cpp:26:19: error: unexpected character <U+2019>
charT one = charT(’1’));
                  ^
p734.cpp:26:23: error: character <U+2019> not allowed in an identifier
charT one = charT(’1’));
                    ^
p734.cpp:26:23: error: invalid suffix '’' on integer constant
p734.cpp:20:12: error: C++ requires a type specifier for all declarations
  explicit bitset(
  ~~~~~~~~ ^
p734.cpp:32:58: error: reference to 'hash' is ambiguous
template<class T> struct hash; template<size_t N> struct hash<bitset<N>>;
                                                         ^
p734.cpp:32:26: note: candidate found by name lookup is 'hash'
template<class T> struct hash; template<size_t N> struct hash<bitset<N>>;
                         ^
/usr/bin/../lib/gcc/x86_64-linux-gnu/10/../../../../include/c++/10/variant:78:30: note: candidate found by name lookup is 'std::hash'
  template <typename> struct hash;
                             ^
p734.cpp:32:63: error: use of undeclared identifier 'bitset'
template<class T> struct hash; template<size_t N> struct hash<bitset<N>>;
                                                              ^
p734.cpp:33:1: error: extraneous closing brace ('}')
}
^
p734.cpp:37:11: error: C++ requires a type specifier for all declarations
constexpr bitset() noexcept;
~~~~~~~~~ ^
p734.cpp:41:12: error: C++ requires a type specifier for all declarations
  explicit bitset(
  ~~~~~~~~ ^
p734.cpp:41:3: error: 'explicit' can only appear on non-static member functions
  explicit bitset(
  ^
p734.cpp:42:1: error: expected expression
template<class charT>
^
p734.cpp:46:20: error: unexpected character <U+2019>
charT zero = charT(’0’),
                   ^
p734.cpp:46:24: error: character <U+2019> not allowed in an identifier
charT zero = charT(’0’),
                     ^
p734.cpp:47:19: error: unexpected character <U+2019>
charT one = charT(’1’));
                  ^
fatal error: too many errors emitted, stopping now [-ferror-limit=]
20 errors generated.

$ g++ p734.cpp -std=03 -o p734g -I. -Wall
In file included from /usr/local/include/c++/12.1.0/atomic:38,
                 from N4910.h:10,
                 from p734.cpp:10:
/usr/local/include/c++/12.1.0/bits/c++0x_warning.h:32:2: error: #error This file requires compiler and library support for the ISO C++ 2011 standard. This support must be enabled with the -std=c++11 or -std=gnu++11 compiler options.
   32 | #error This file requires compiler and library support \
      |  ^~~~~
p734.cpp:15:1: warning: identifier 'constexpr' is a keyword in C++11 [-Wc++11-compat]
   15 | constexpr bitset() noexcept;
      | ^~~~~~~~~
p734.cpp:15:20: warning: identifier 'noexcept' is a keyword in C++11 [-Wc++11-compat]
   15 | constexpr bitset() noexcept;
      |                    ^~~~~~~~
p734.cpp:25:20: error: extended character ’ is not valid in an identifier
   25 | charT zero = charT(’0’),
      |                    ^
p734.cpp:25:20: error: extended character ’ is not valid in an identifier
p734.cpp:26:19: error: extended character ’ is not valid in an identifier
   26 | charT one = charT(’1’));
      |                   ^
p734.cpp:26:19: error: extended character ’ is not valid in an identifier
p734.cpp:46:20: error: extended character ’ is not valid in an identifier
   46 | charT zero = charT(’0’),
      |                    ^
p734.cpp:46:20: error: extended character ’ is not valid in an identifier
p734.cpp:47:19: error: extended character ’ is not valid in an identifier
   47 | charT one = charT(’1’));
      |                   ^
p734.cpp:47:19: error: extended character ’ is not valid in an identifier
p734.cpp:15:1: error: 'constexpr' does not name a type
   15 | constexpr bitset() noexcept;
      | ^~~~~~~~~
p734.cpp:15:1: note: C++11 'constexpr' only available with '-std=c++11' or '-std=gnu++11'
p734.cpp:17:1: error: 'constexpr' does not name a type
   17 | constexpr bitset(unsigned long long val) noexcept;
      | ^~~~~~~~~
p734.cpp:17:1: note: C++11 'constexpr' only available with '-std=c++11' or '-std=gnu++11'
p734.cpp:25:20: error: '\U000020190\U00002019' was not declared in this scope
   25 | charT zero = charT(’0’),
      |                    ^~~
p734.cpp:26:19: error: '\U000020191\U00002019' was not declared in this scope
   26 | charT one = charT(’1’));
      |                   ^~~
p734.cpp:20:12: error: ISO C++ forbids declaration of 'bitset' with no type [-fpermissive]
   20 |   explicit bitset(
      |            ^~~~~~
p734.cpp:20:3: error: 'explicit' outside class declaration
   20 |   explicit bitset(
      |   ^~~~~~~~
p734.cpp:32:71: warning: '>>' operator is treated as two right angle brackets in C++11 [-Wc++11-compat]
   32 | template<class T> struct hash; template<size_t N> struct hash<bitset<N>>;
      |                                                                       ^~
p734.cpp:32:71: note: suggest parentheses around '>>' expression
p734.cpp:32:63: error: parse error in template argument list
   32 | template<class T> struct hash; template<size_t N> struct hash<bitset<N>>;
      |                                                               ^~~~~~~~~~
p734.cpp:32:63: error: type/value mismatch at argument 1 in template parameter list for 'template<class T> struct hash'
p734.cpp:32:63: note:   expected a type, got 'bitset<<expression error> >'
p734.cpp:33:1: error: expected declaration before '}' token
   33 | }
      | ^
p734.cpp:37:1: error: 'constexpr' does not name a type
   37 | constexpr bitset() noexcept;
      | ^~~~~~~~~
p734.cpp:37:1: note: C++11 'constexpr' only available with '-std=c++11' or '-std=gnu++11'
p734.cpp:41:12: error: ISO C++ forbids declaration of 'bitset' with no type [-fpermissive]
   41 |   explicit bitset(
      |            ^~~~~~
p734.cpp:41:3: error: 'explicit' outside class declaration
   41 |   explicit bitset(
      |   ^~~~~~~~
p734.cpp:41:18: error: 'template<class charT, class traits, class Allocator> int bitset' conflicts with a previous declaration
   41 |   explicit bitset(
      |                  ^
p734.cpp:20:12: note: previous declaration 'int bitset(const std::__cxx11::basic_string<_CharT, _Traits, _Alloc>&, typename std::__cxx11::basic_string<_CharT, _Traits, _Alloc>::size_type, typename std::__cxx11::basic_string<_CharT, _Traits, _Alloc>::size_type, charT, charT)'
   20 |   explicit bitset(
      |            ^~~~~~
p734.cpp:42:1: error: expected primary-expression before 'template'
   42 | template<class charT>
      | ^~~~~~~~
p734.cpp:41:12: warning: variable templates only available with '-std=c++14' or '-std=gnu++14' [-Wc++14-extensions]
   41 |   explicit bitset(
      |            ^~~~~~
p734.cpp:49:10: error: expected constructor, destructor, or type conversion before '(' token
   49 |    bitset(n == basic_string<charT>::npos
      |          ^

$ g++ p734.cpp -std=2b -o p734g -I. -Wall
p734.cpp:25:20: error: extended character ’ is not valid in an identifier
   25 | charT zero = charT(’0’),
      |                    ^
p734.cpp:25:20: error: extended character ’ is not valid in an identifier
p734.cpp:26:19: error: extended character ’ is not valid in an identifier
   26 | charT one = charT(’1’));
      |                   ^
p734.cpp:26:19: error: extended character ’ is not valid in an identifier
p734.cpp:46:20: error: extended character ’ is not valid in an identifier
   46 | charT zero = charT(’0’),
      |                    ^
p734.cpp:46:20: error: extended character ’ is not valid in an identifier
p734.cpp:47:19: error: extended character ’ is not valid in an identifier
   47 | charT one = charT(’1’));
      |                   ^
p734.cpp:47:19: error: extended character ’ is not valid in an identifier
p734.cpp:15:11: error: ISO C++ forbids declaration of 'bitset' with no type [-fpermissive]
   15 | constexpr bitset() noexcept;
      |           ^~~~~~
p734.cpp:17:11: error: ISO C++ forbids declaration of 'bitset' with no type [-fpermissive]
   17 | constexpr bitset(unsigned long long val) noexcept;
      |           ^~~~~~
p734.cpp:25:20: error: '\U000020190\U00002019' was not declared in this scope
   25 | charT zero = charT(’0’),
      |                    ^~~
p734.cpp:26:19: error: '\U000020191\U00002019' was not declared in this scope
   26 | charT one = charT(’1’));
      |                   ^~~
p734.cpp:20:12: error: ISO C++ forbids declaration of 'bitset' with no type [-fpermissive]
   20 |   explicit bitset(
      |            ^~~~~~
p734.cpp:20:3: error: 'explicit' outside class declaration
   20 |   explicit bitset(
      |   ^~~~~~~~
p734.cpp:32:58: error: 'hash' is not a class template
   32 | template<class T> struct hash; template<size_t N> struct hash<bitset<N>>;
      |                                                          ^~~~
p734.cpp:32:10: error: template parameter 'class T'
   32 | template<class T> struct hash; template<size_t N> struct hash<bitset<N>>;
      |          ^~~~~
p734.cpp:32:48: note: redeclared here as 'long unsigned int N'
   32 | template<class T> struct hash; template<size_t N> struct hash<bitset<N>>;
      |                                                ^
p734.cpp:33:1: error: expected declaration before '}' token
   33 | }
      | ^
p734.cpp:37:11: error: ISO C++ forbids declaration of 'bitset' with no type [-fpermissive]
   37 | constexpr bitset() noexcept;
      |           ^~~~~~
p734.cpp:41:12: error: ISO C++ forbids declaration of 'bitset' with no type [-fpermissive]
   41 |   explicit bitset(
      |            ^~~~~~
p734.cpp:41:3: error: 'explicit' outside class declaration
   41 |   explicit bitset(
      |   ^~~~~~~~
p734.cpp:41:18: error: 'template<class charT, class traits, class Allocator> int bitset' redeclared as different kind of entity
   41 |   explicit bitset(
      |                  ^
p734.cpp:17:11: note: previous declaration 'constexpr int bitset(long long unsigned int)'
   17 | constexpr bitset(unsigned long long val) noexcept;
      |           ^~~~~~
p734.cpp:42:1: error: expected primary-expression before 'template'
   42 | template<class charT>
      | ^~~~~~~~
p734.cpp:49:10: error: expected constructor, destructor, or type conversion before '(' token
   49 |    bitset(n == basic_string<charT>::npos
      |          ^

```

## 検討事項(agenda)
コンパイルエラーを取るか、コンパイルエラーの理由を解説する。

<!-- リンクエラーの解説をする。clang++とg++の比較。意味のある出力。
コンパイルエラーを取るか、コンパイルエラーの理由を解説する。-->

# 参考資料(reference)

@kazuo_reve 私が効果を確認した「小川メソッド」

https://qiita.com/kazuo_reve/items/a3ea1d9171deeccc04da

## 自己参照(self reference)

関連する自己参照以外は、こちらの先頭に移転。

C言語（C++)に対する誤解、曲解、無理解、爽快。

https://qiita.com/kaizen_nagoya/items/3f3992c9722c1cee2e3a

#include "N4910.h"

https://qiita.com/kaizen_nagoya/items/163a47cef7d6bb1c33a8

C++N4910資料の改善点

https://qiita.com/kaizen_nagoya/items/fb4ceb5d117a54641af3

ockerにclang

https://qiita.com/kaizen_nagoya/items/8829ffeee397eda50e80

docker gnu(gcc/g++) and llvm(clang/clang++)

https://qiita.com/drafts/059874ea39c4de64c0f7

コンパイル用shell script C版(clangとgcc)とC++版(clang++とg++)

https://qiita.com/kaizen_nagoya/items/74220c0577a512c2d7da

C++N4910:2022 tag follower 200人超えました。ありがとうございます。

https://qiita.com/kaizen_nagoya/items/a63fb96d351ac5c16ff7

C++N4910:2022 tag follower 200人超えました。ありがとうございます。

https://qiita.com/kaizen_nagoya/items/a63fb96d351ac5c16ff7

コピペコンパイルエラーあるある

https://qiita.com/kaizen_nagoya/items/29c832de9d762aed2761

C++ Error Message Collection(1)does not name a type, 11 articles

https://qiita.com/kaizen_nagoya/items/acb9f1a9b5aad6df06bd

dockerにclang

https://qiita.com/kaizen_nagoya/items/8829ffeee397eda50e80

docker gnu(gcc/g++) and llvm(clang/clang++)

https://qiita.com/kaizen_nagoya/items/059874ea39c4de64c0f7

Compare the contents of C++N4910:2022, C++N4741:2018 and C++N4606:2015

https://qiita.com/kaizen_nagoya/items/483246d40f98abff7ded

C++ sample list

https://qiita.com/kaizen_nagoya/items/54ad75b73825b7c04f86

clang++, g++コンパイルエラー方針の違いの例

https://qiita.com/kaizen_nagoya/items/ea6e5009fe126d270a82

astyle 使ってみた

https://qiita.com/kaizen_nagoya/items/3c9a87a781d53a1a23f3

DoCAP（ドゥーキャップ）って何ですか？

https://qiita.com/kaizen_nagoya/items/47e0e6509ab792c43327

小川メソッド　覚え（書きかけ）

https://qiita.com/kaizen_nagoya/items/3593d72eca551742df68

 ＜この記事は個人の過去の経験に基づく個人の感想です。現在所属する組織、業務とは関係がありません。＞

# 文書履歴(document history)
ver. 0.01 初稿 　20220730

C++N4910 AdventCalendar2022 DoCAP coding 小川メソッド