mirror of git://git.qorg11.net/kill9.git
213 lines
11 KiB
Markdown
213 lines
11 KiB
Markdown
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<style>
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pre {
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overflow:auto;
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table-layout:fixed;
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width: 75%;
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max-width:75%;
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}
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</style>
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# C++ sucks
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>C makes it easy to shoot yourself in the foot; C++ makes it harder,
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>but when you do, it blows away your whole leg.
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--- Bjarne Stroustrup
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>If you like C++, you don’t know C++. There’s a mutual exclusion going
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>on here, and I’ve yet to see a counter-example other than possibly a
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>few of the members of the standards committee.
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--- ssylvan
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## Object oriented
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So automatically sucks.
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## Ugly syntax
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The only non-ugly part of C++ is the headers' name: iostream, cmath,
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ctime, thread, etc. Unlike in C, where they are ugly as shit: stdio.h,
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unistd.h, stdlib.h, pthreads.h...
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But the rest of the language has the ugliest syntax that I've ever seen:
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Hello world in C++
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~~~
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#include <iostream>
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int main(void)
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{
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std::cout << "Hello world!" << std:endl;
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}
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~~~
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Now what the fuck is std:: and why do I have to write << just to print some shit.
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Note: you can skip the std:: part with ```using namespace std``` but this is a [bad practice](https://stackoverflow.com/questions/1452721/why-is-using-namespace-std-considered-bad-practice)
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## Error messages
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in the following code:
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~~~
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#include <iostream>
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int main(void)
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{
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std::cout < "Hello world!" < std:endl;
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}
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~~~
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You get this error message:
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<p class="code">
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~~~
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a.cc: In function ‘int main()’:
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a.cc:5:13: error: no match for ‘operator<’ (operand types are ‘std::ostream’ {aka ‘std::basic_ostream<char>’} and ‘const char [13]’)
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5 | std::cout < "Hello world!" < std:endl;
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| ~~~~~~~~~ ^ ~~~~~~~~~~~~~~
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| | |
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| | const char [13]
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| std::ostream {aka std::basic_ostream<char>}
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In file included from /usr/local/include/c++/10.0.1/bits/stl_algobase.h:64,
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from /usr/local/include/c++/10.0.1/bits/char_traits.h:39,
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from /usr/local/include/c++/10.0.1/ios:40,
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from /usr/local/include/c++/10.0.1/ostream:38,
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from /usr/local/include/c++/10.0.1/iostream:39,
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from a.cc:1:
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/usr/local/include/c++/10.0.1/bits/stl_pair.h:489:5: note: candidate: ‘template<class _T1, class _T2> constexpr bool std::operator<(const std::pair<_T1, _T2>&, const std::pair<_T1, _T2>&)’
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489 | operator<(const pair<_T1, _T2>& __x, const pair<_T1, _T2>& __y)
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| ^~~~~~~~
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/usr/local/include/c++/10.0.1/bits/stl_pair.h:489:5: note: template argument deduction/substitution failed:
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a.cc:5:15: note: ‘std::ostream’ {aka ‘std::basic_ostream<char>’} is not derived from ‘const std::pair<_T1, _T2>’
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5 | std::cout < "Hello world!" < std:endl;
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| ^~~~~~~~~~~~~~
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In file included from /usr/local/include/c++/10.0.1/bits/stl_algobase.h:67,
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from /usr/local/include/c++/10.0.1/bits/char_traits.h:39,
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from /usr/local/include/c++/10.0.1/ios:40,
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from /usr/local/include/c++/10.0.1/ostream:38,
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from /usr/local/include/c++/10.0.1/iostream:39,
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from a.cc:1:
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/usr/local/include/c++/10.0.1/bits/stl_iterator.h:366:5: note: candidate: ‘template<class _Iterator> bool std::operator<(const std::reverse_iterator<_Iterator>&, const std::reverse_iterator<_Iterator>&)’
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366 | operator<(const reverse_iterator<_Iterator>& __x,
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| ^~~~~~~~
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/usr/local/include/c++/10.0.1/bits/stl_iterator.h:366:5: note: template argument deduction/substitution failed:
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a.cc:5:15: note: ‘std::ostream’ {aka ‘std::basic_ostream<char>’} is not derived from ‘const std::reverse_iterator<_Iterator>’
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5 | std::cout < "Hello world!" < std:endl;
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| ^~~~~~~~~~~~~~
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In file included from /usr/local/include/c++/10.0.1/bits/stl_algobase.h:67,
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from /usr/local/include/c++/10.0.1/bits/char_traits.h:39,
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from /usr/local/include/c++/10.0.1/ios:40,
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from /usr/local/include/c++/10.0.1/ostream:38,
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from /usr/local/include/c++/10.0.1/iostream:39,
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from a.cc:1:
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/usr/local/include/c++/10.0.1/bits/stl_iterator.h:404:5: note: candidate: ‘template<class _IteratorL, class _IteratorR> bool std::operator<(const std::reverse_iterator<_Iterator>&, const std::reverse_iterator<_IteratorR>&)’
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404 | operator<(const reverse_iterator<_IteratorL>& __x,
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| ^~~~~~~~
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/usr/local/include/c++/10.0.1/bits/stl_iterator.h:404:5: note: template argument deduction/substitution failed:
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a.cc:5:15: note: ‘std::ostream’ {aka ‘std::basic_ostream<char>’} is not derived from ‘const std::reverse_iterator<_Iterator>’
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5 | std::cout < "Hello world!" < std:endl;
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| ^~~~~~~~~~~~~~
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In file included from /usr/local/include/c++/10.0.1/bits/stl_algobase.h:67,
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from /usr/local/include/c++/10.0.1/bits/char_traits.h:39,
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from /usr/local/include/c++/10.0.1/ios:40,
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from /usr/local/include/c++/10.0.1/ostream:38,
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from /usr/local/include/c++/10.0.1/iostream:39,
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from a.cc:1:
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/usr/local/include/c++/10.0.1/bits/stl_iterator.h:1451:5: note: candidate: ‘template<class _IteratorL, class _IteratorR> bool std::operator<(const std::move_iterator<_IteratorL>&, const std::move_iterator<_IteratorR>&)’
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1451 | operator<(const move_iterator<_IteratorL>& __x,
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| ^~~~~~~~
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/usr/local/include/c++/10.0.1/bits/stl_iterator.h:1451:5: note: template argument deduction/substitution failed:
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a.cc:5:15: note: ‘std::ostream’ {aka ‘std::basic_ostream<char>’} is not derived from ‘const std::move_iterator<_IteratorL>’
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5 | std::cout < "Hello world!" < std:endl;
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| ^~~~~~~~~~~~~~
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In file included from /usr/local/include/c++/10.0.1/bits/stl_algobase.h:67,
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from /usr/local/include/c++/10.0.1/bits/char_traits.h:39,
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from /usr/local/include/c++/10.0.1/ios:40,
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from /usr/local/include/c++/10.0.1/ostream:38,
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from /usr/local/include/c++/10.0.1/iostream:39,
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from a.cc:1:
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/usr/local/include/c++/10.0.1/bits/stl_iterator.h:1507:5: note: candidate: ‘template<class _Iterator> bool std::operator<(const std::move_iterator<_IteratorL>&, const std::move_iterator<_IteratorL>&)’
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1507 | operator<(const move_iterator<_Iterator>& __x,
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| ^~~~~~~~
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/usr/local/include/c++/10.0.1/bits/stl_iterator.h:1507:5: note: template argument deduction/substitution failed:
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a.cc:5:15: note: ‘std::ostream’ {aka ‘std::basic_ostream<char>’} is not derived from ‘const std::move_iterator<_IteratorL>’
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5 | std::cout < "Hello world!" < std:endl;
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| ^~~~~~~~~~~~~~
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In file included from /usr/local/include/c++/10.0.1/string:55,
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from /usr/local/include/c++/10.0.1/bits/locale_classes.h:40,
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from /usr/local/include/c++/10.0.1/bits/ios_base.h:41,
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from /usr/local/include/c++/10.0.1/ios:42,
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from /usr/local/include/c++/10.0.1/ostream:38,
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from /usr/local/include/c++/10.0.1/iostream:39,
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from a.cc:1:
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/usr/local/include/c++/10.0.1/bits/basic_string.h:6267:5: note: candidate: ‘template<class _CharT, class _Traits, class _Alloc> bool std::operator<(const std::__cxx11::basic_string<_CharT, _Traits, _Alloc>&, const std::__cxx11::basic_string<_CharT, _Traits, _Alloc>&)’
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6267 | operator<(const basic_string<_CharT, _Traits, _Alloc>& __lhs,
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| ^~~~~~~~
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/usr/local/include/c++/10.0.1/bits/basic_string.h:6267:5: note: template argument deduction/substitution failed:
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a.cc:5:15: note: ‘std::ostream’ {aka ‘std::basic_ostream<char>’} is not derived from ‘const std::__cxx11::basic_string<_CharT, _Traits, _Alloc>’
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5 | std::cout < "Hello world!" < std:endl;
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| ^~~~~~~~~~~~~~
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In file included from /usr/local/include/c++/10.0.1/string:55,
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from /usr/local/include/c++/10.0.1/bits/locale_classes.h:40,
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from /usr/local/include/c++/10.0.1/bits/ios_base.h:41,
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from /usr/local/include/c++/10.0.1/ios:42,
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from /usr/local/include/c++/10.0.1/ostream:38,
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from /usr/local/include/c++/10.0.1/iostream:39,
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from a.cc:1:
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/usr/local/include/c++/10.0.1/bits/basic_string.h:6280:5: note: candidate: ‘template<class _CharT, class _Traits, class _Alloc> bool std::operator<(const std::__cxx11::basic_string<_CharT, _Traits, _Alloc>&, const _CharT*)’
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6280 | operator<(const basic_string<_CharT, _Traits, _Alloc>& __lhs,
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| ^~~~~~~~
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/usr/local/include/c++/10.0.1/bits/basic_string.h:6280:5: note: template argument deduction/substitution failed:
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a.cc:5:15: note: ‘std::ostream’ {aka ‘std::basic_ostream<char>’} is not derived from ‘const std::__cxx11::basic_string<_CharT, _Traits, _Alloc>’
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5 | std::cout < "Hello world!" < std:endl;
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| ^~~~~~~~~~~~~~
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In file included from /usr/local/include/c++/10.0.1/string:55,
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from /usr/local/include/c++/10.0.1/bits/locale_classes.h:40,
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from /usr/local/include/c++/10.0.1/bits/ios_base.h:41,
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from /usr/local/include/c++/10.0.1/ios:42,
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from /usr/local/include/c++/10.0.1/ostream:38,
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from /usr/local/include/c++/10.0.1/iostream:39,
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from a.cc:1:
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/usr/local/include/c++/10.0.1/bits/basic_string.h:6292:5: note: candidate: ‘template<class _CharT, class _Traits, class _Alloc> bool std::operator<(const _CharT*, const std::__cxx11::basic_string<_CharT, _Traits, _Alloc>&)’
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6292 | operator<(const _CharT* __lhs,
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| ^~~~~~~~
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/usr/local/include/c++/10.0.1/bits/basic_string.h:6292:5: note: template argument deduction/substitution failed:
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a.cc:5:15: note: mismatched types ‘const _CharT*’ and ‘std::basic_ostream<char>’
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5 | std::cout < "Hello world!" < std:endl;
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| ^~~~~~~~~~~~~~
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In file included from /usr/local/include/c++/10.0.1/bits/ios_base.h:46,
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from /usr/local/include/c++/10.0.1/ios:42,
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from /usr/local/include/c++/10.0.1/ostream:38,
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from /usr/local/include/c++/10.0.1/iostream:39,
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from a.cc:1:
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/usr/local/include/c++/10.0.1/system_error:252:3: note: candidate: ‘bool std::operator<(const std::error_code&, const std::error_code&)’
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252 | operator<(const error_code& __lhs, const error_code& __rhs) noexcept
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| ^~~~~~~~
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/usr/local/include/c++/10.0.1/system_error:252:31: note: no known conversion for argument 1 from ‘std::ostream’ {aka ‘std::basic_ostream<char>’} to ‘const std::error_code&’
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252 | operator<(const error_code& __lhs, const error_code& __rhs) noexcept
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| ~~~~~~~~~~~~~~~~~~^~~~~
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/usr/local/include/c++/10.0.1/system_error:379:3: note: candidate: ‘bool std::operator<(const std::error_condition&, const std::error_condition&)’
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379 | operator<(const error_condition& __lhs,
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| ^~~~~~~~
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/usr/local/include/c++/10.0.1/system_error:379:36: note: no known conversion for argument 1 from ‘std::ostream’ {aka ‘std::basic_ostream<char>’} to ‘const std::error_condition&’
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379 | operator<(const error_condition& __lhs,
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| ~~~~~~~~~~~~~~~~~~~~~~~^~~~~
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a.cc:5:35: error: found ‘:’ in nested-name-specifier, expected ‘::’
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5 | std::cout < "Hello world!" < std:endl;
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| ^
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| ::
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~~~
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</p>
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(In GCC)
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## Compatibilty
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C++ is "compatible" with C
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But this can break most C programs
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