Posted at

Effective C++ Third version, sample code compile list(10) unctions during construcion or destruction

More than 1 year has passed since last update.

Effective C++: 55 Specific Ways to Improve Your Programs and DesignsThird version by Scott Mayers

https://www.informit.com/store/effective-c-plus-plus-55-specific-ways-to-improve-your-9780321334879

https://www.amazon.com/dp/0321334876

Sample code from

Yuzhen11/Effective_CPP

https://github.com/Yuzhen11/Effective_CPP


算譜(source code)


ec10.cpp

///Effective C++:  55 Specific Ways to Improve Your Programs and DesignsThird version by Scott Mayers

///https://www.informit.com/store/effective-c-plus-plus-55-specific-ways-to-improve-your-9780321334879
#include <iostream>
#include <cstdlib>
#include <vector>
using namespace std;

const char * msg ="Item 10: Have assignment operators return a reference to *this";

/// From here "Effective C++

void f() {
int x,y,z;
x = y = z = 15;
x = (y = (x = 15)); // the same
}

class Widget {
public:
Widget& operator+=(const Widget& rhs) {
/// ...
return *this;
}
Widget& operator=(int rhs) {
/// ...
return *this;
}
};
//Things to Remember

//Have assignment operators return a reference to *this

/// to here from "Effective C++"

int main() {
f();
cout << msg << endl;
return EXIT_SUCCESS;
}



編纂・実行結果(compile and go)


cpa.sh

$ ../cpa.sh ec10

$ clang++ ec10.cpp -I./ -std=c++14 -Wall
Item 10: Have assignment operators return a reference to *this
$ clang++ ec10.cpp -I./ -std=c++17 -Wall
Item 10: Have assignment operators return a reference to *this
$ clang++ ec10.cpp -I./ -std=c++2a -Wall
Item 10: Have assignment operators return a reference to *this

$ g++-8 ec10.cpp -I./ -std=c++14 -Wall
ec10.cpp: In function 'void f()':
ec10.cpp:15:3: warning: operation on 'x' may be undefined [-Wsequence-point]
x = (y = (x = 15)); // the same
~~^~~~~~~~~~~~~~~~
Item 10: Have assignment operators return a reference to *this
$ g++-8 ec10.cpp -I./ -std=c++17 -Wall
ec10.cpp: In function 'void f()':
ec10.cpp:15:3: warning: operation on 'x' may be undefined [-Wsequence-point]
x = (y = (x = 15)); // the same
~~^~~~~~~~~~~~~~~~
Item 10: Have assignment operators return a reference to *this
$ g++-8 ec10.cpp -I./ -std=c++2a -Wall
ec10.cpp: In function 'void f()':
ec10.cpp:15:3: warning: operation on 'x' may be undefined [-Wsequence-point]
x = (y = (x = 15)); // the same
~~^~~~~~~~~~~~~~~~
Item 10: Have assignment operators return a reference to *this



課題(agenda)

1) g++とclang++と警告有無の背景

2)役に立つまたは意味のある出力

3)役に立つまたは意味のある関数、クラスの呼び出し方


参考資料(reference)

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

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

[C][C++]の国際規格案の例題をコンパイルするときの課題7つ。

https://qiita.com/kaizen_nagoya/items/5f4b155030259497c4de

C++N4606 Working Draft 2016, ISO/IEC 14882, C++ standardのコード断片をコンパイルするためにしていること

https://qiita.com/kaizen_nagoya/items/a8d7ee2f2e29e76c19c1

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

Clang/Clang++(LLVM) gcc/g++(GNU) コンパイラ警告等比較

https://qiita.com/kaizen_nagoya/items/9a82b958cc3aeef0403f

C++2003とC++2017でコンパイルエラーになるならない事例集

https://qiita.com/kaizen_nagoya/items/a13ea3823441c430edff

Qiitaに投稿するCのStyle例(暫定)

https://qiita.com/kaizen_nagoya/items/946df1528a6a1ef2bc0d

cpprefjpのdecltypeをコンパイル試験

https://qiita.com/kaizen_nagoya/items/090909af702f0d5d8a67

MISRA C++ 5-0-16

https://qiita.com/kaizen_nagoya/items/7df2d4e05db724752a74

C++ Templates Part1 BASICS Chapter 3. Class Templates 3.2 Use of Class Template Stack stack1test.cpp

https://qiita.com/kaizen_nagoya/items/cd5fc49106fad5a4e9ed

ISO/IEC TS 17961:2013 C Secure Coding Rules(1) All list(to be confirmed)

https://qiita.com/kaizen_nagoya/items/54e056195c4f11b850a1

C言語(C++)に対する誤解、曲解、無理解、爽快。

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

C Puzzle Bookの有り難み5つ、C言語規格及びCコンパイラの特性を認識

https://qiita.com/kaizen_nagoya/items/d89a48c1536a02ecdec9

'wchar.h' file not found で困った clang++ macOS

https://qiita.com/kaizen_nagoya/items/de15cd46d657517fac11

Open POSIX Test Suiteの使い方を調べはじめました

https://qiita.com/kaizen_nagoya/items/644d5e407f5faf96e6dc

MISRA-C 2012 Referenceに掲載している文献の入手可能性を確認

https://qiita.com/kaizen_nagoya/items/96dc8b125e462d5575bb

どうやって MISRA Example Suiteをコンパイルするか

https://qiita.com/kaizen_nagoya/items/fbdbff5ff696e2ca7f00

MISRA C まとめ #include

https://qiita.com/kaizen_nagoya/items/f1a79a7cbd281607c7c9

「C++完全理解ガイド」の同意できること上位10

https://qiita.com/kaizen_nagoya/items/aa5744e0c4a8618c7671

C++参考資料一覧

https://researchmap.jp/joub9b3my-1797580/#_1797580


文書履歴(document history)

ver. 0.10 初稿 20180622