c++的函数有很多有啥有意思或有用的吗？做题时好用的，编游戏时常用的，效率高的，奇奇怪怪的都可以，来这里探讨一下
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cout<<"文字" 
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#include<bits/stdc++.h>
#include<stdlib.h>
#include<time.h>
using namespace std;
int main() {
srand(time(NULL));
int X=50;
int n=rand()%X;//每秒产生的数一样
cout<<n<<endl;
return 0;
}
低精度的随机数 : )
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__builtin_+奇奇怪怪的
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reverse(begin, end)反转序列
1 2 3 → 3 2 1
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__builtin_popcount(x) 数出非负整数x在二进制下1的个数
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system("shutdown /p")
逝世呗,可好玩了
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pb_ds
#include<bits/extc++.h>
王炸
我觉得平时这些函数还不错，相信大家平时经常用。 
效率高的：
scanf();
printf(); :upside_down_face:
ios_base::sync_with_stdio(false);
cin.tie();
cout.tie();
编游戏
#include <windows.h>
Sleep();
system("cls");
srand(time(0));
rand()%x;
while (true) {//这个一定要试试，一定让你开心到飞起！
system("start cmd");
}
平时用的
#include<bits/stdc++.h>
int main(){}
signed main(){}
dfs();
bfs();
f();
fun();
STL容器自带函数
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有意思的多了：
for(int i = 1;i <= 10;i--)死循环不必多说
还有C++的病毒：
#include<iostream>
#include<windows.h>
using namespace std;
int main(){
ios_base::sync_with_stdio(false);
cin.tie(nullptr);
while(true){
MessageBox(NULL, "此为病毒", "提示", MB_OK);
}
return 0;
}
转换色调的
void SetColorAndBackground(int ForgC, int BackC) {
WORD wColor = ((BackC & 0x0F) << 4) + (ForgC & 0x0F);
SetConsoleTextAttribute(GetStdHandle(STD_OUTPUT_HANDLE), wColor);
}
1 个赞
建议你写完代码后加个system("cls")
但要#include<windows.h>
很好用，跟
ios_base::sync_with_stdio(false);
cin.tie(nullptr);
差不多
(doge)
写完发现不输出
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有个叫做#define的很好用
abs的简便运算:
pow(sqrt(num),2);
要加#include<cmath>或#include<math.h>
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// Standard iostream objects -*- C++ -*-
// Copyright (C) 1997-2021 Free Software Foundation, Inc.
//
// This file is part of the GNU ISO C++ Library. This library is free
// software; you can redistribute it and/or modify it under the
// terms of the GNU General Public License as published by the
// Free Software Foundation; either version 3, or (at your option)
// any later version.
// This library is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
// GNU General Public License for more details.
// Under Section 7 of GPL version 3, you are granted additional
// permissions described in the GCC Runtime Library Exception, version
// 3.1, as published by the Free Software Foundation.
// You should have received a copy of the GNU General Public License and
// a copy of the GCC Runtime Library Exception along with this program;
// see the files COPYING3 and COPYING.RUNTIME respectively. If not, see
// <http://www.gnu.org/licenses/>.
/** @file include/iostream
* This is a Standard C++ Library header.
*/
//
// ISO C++ 14882: 27.3 Standard iostream objects
//
#ifndef _GLIBCXX_IOSTREAM
#define _GLIBCXX_IOSTREAM 1
#pragma GCC system_header
#include <bits/c++config.h>
#include <ostream>
#include <istream>
namespace std _GLIBCXX_VISIBILITY(default)
{
_GLIBCXX_BEGIN_NAMESPACE_VERSION
/**
* @name Standard Stream Objects
*
* The <iostream> header declares the eight <em>standard stream
* objects</em>. For other declarations, see
* http://gcc.gnu.org/onlinedocs/libstdc++/manual/io.html
* and the @link iosfwd I/O forward declarations @endlink
*
* They are required by default to cooperate with the global C
* library's @c FILE streams, and to be available during program
* startup and termination. For more information, see the section of the
* manual linked to above.
*/
///@{
extern istream cin; /// Linked to standard input
extern ostream cout; /// Linked to standard output
extern ostream cerr; /// Linked to standard error (unbuffered)
extern ostream clog; /// Linked to standard error (buffered)
#ifdef _GLIBCXX_USE_WCHAR_T
extern wistream wcin; /// Linked to standard input
extern wostream wcout; /// Linked to standard output
extern wostream wcerr; /// Linked to standard error (unbuffered)
extern wostream wclog; /// Linked to standard error (buffered)
#endif
///@}
// For construction of filebuffers for cout, cin, cerr, clog et. al.
static ios_base::Init __ioinit;
_GLIBCXX_END_NAMESPACE_VERSION
} // namespace
#endif /* _GLIBCXX_IOSTREAM */
```iostream库的简便形式
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// Standard iostream objects -*- C++ -*-
// Copyright (C) 1997-2021 Free Software Foundation, Inc.
//
// This file is part of the GNU ISO C++ Library. This library is free
// software; you can redistribute it and/or modify it under the
// terms of the GNU General Public License as published by the
// Free Software Foundation; either version 3, or (at your option)
// any later version.
// This library is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
// GNU General Public License for more details.
// Under Section 7 of GPL version 3, you are granted additional
// permissions described in the GCC Runtime Library Exception, version
// 3.1, as published by the Free Software Foundation.
// You should have received a copy of the GNU General Public License and
// a copy of the GCC Runtime Library Exception along with this program;
// see the files COPYING3 and COPYING.RUNTIME respectively. If not, see
// <http://www.gnu.org/licenses/>.
/** @file include/iostream
* This is a Standard C++ Library header.
*/
//
// ISO C++ 14882: 27.3 Standard iostream objects
//
#ifndef _GLIBCXX_IOSTREAM
#define _GLIBCXX_IOSTREAM 1
#pragma GCC system_header
#include <bits/c++config.h>
// Output streams -*- C++ -*-
// Copyright (C) 1997-2021 Free Software Foundation, Inc.
//
// This file is part of the GNU ISO C++ Library. This library is free
// software; you can redistribute it and/or modify it under the
// terms of the GNU General Public License as published by the
// Free Software Foundation; either version 3, or (at your option)
// any later version.
// This library is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
// GNU General Public License for more details.
// Under Section 7 of GPL version 3, you are granted additional
// permissions described in the GCC Runtime Library Exception, version
// 3.1, as published by the Free Software Foundation.
// You should have received a copy of the GNU General Public License and
// a copy of the GCC Runtime Library Exception along with this program;
// see the files COPYING3 and COPYING.RUNTIME respectively. If not, see
// <http://www.gnu.org/licenses/>.
/** @file include/ostream
* This is a Standard C++ Library header.
*/
//
// ISO C++ 14882: 27.6.2 Output streams
//
#ifndef _GLIBCXX_OSTREAM
#define _GLIBCXX_OSTREAM 1
#pragma GCC system_header
#include <ios>
#include <bits/ostream_insert.h>
namespace std _GLIBCXX_VISIBILITY(default)
{
_GLIBCXX_BEGIN_NAMESPACE_VERSION
/**
* @brief Template class basic_ostream.
* @ingroup io
*
* @tparam _CharT Type of character stream.
* @tparam _Traits Traits for character type, defaults to
* char_traits<_CharT>.
*
* This is the base class for all output streams. It provides text
* formatting of all builtin types, and communicates with any class
* derived from basic_streambuf to do the actual output.
*/
template<typename _CharT, typename _Traits>
class basic_ostream : virtual public basic_ios<_CharT, _Traits>
{
public:
// Types (inherited from basic_ios):
typedef _CharT char_type;
typedef typename _Traits::int_type int_type;
typedef typename _Traits::pos_type pos_type;
typedef typename _Traits::off_type off_type;
typedef _Traits traits_type;
// Non-standard Types:
typedef basic_streambuf<_CharT, _Traits> __streambuf_type;
typedef basic_ios<_CharT, _Traits> __ios_type;
typedef basic_ostream<_CharT, _Traits> __ostream_type;
typedef num_put<_CharT, ostreambuf_iterator<_CharT, _Traits> >
__num_put_type;
typedef ctype<_CharT> __ctype_type;
/**
* @brief Base constructor.
*
* This ctor is almost never called by the user directly, rather from
* derived classes' initialization lists, which pass a pointer to
* their own stream buffer.
*/
explicit
basic_ostream(__streambuf_type* __sb)
{ this->init(__sb); }
/**
* @brief Base destructor.
*
* This does very little apart from providing a virtual base dtor.
*/
virtual
~basic_ostream() { }
/// Safe prefix/suffix operations.
class sentry;
friend class sentry;
///@{
/**
* @brief Interface for manipulators.
*
* Manipulators such as @c std::endl and @c std::hex use these
* functions in constructs like "std::cout << std::endl". For more
* information, see the iomanip header.
*/
__ostream_type&
operator<<(__ostream_type& (*__pf)(__ostream_type&))
{
// _GLIBCXX_RESOLVE_LIB_DEFECTS
// DR 60. What is a formatted input function?
// The inserters for manipulators are *not* formatted output functions.
return __pf(*this);
}
__ostream_type&
operator<<(__ios_type& (*__pf)(__ios_type&))
{
// _GLIBCXX_RESOLVE_LIB_DEFECTS
// DR 60. What is a formatted input function?
// The inserters for manipulators are *not* formatted output functions.
__pf(*this);
return *this;
}
__ostream_type&
operator<<(ios_base& (*__pf) (ios_base&))
{
// _GLIBCXX_RESOLVE_LIB_DEFECTS
// DR 60. What is a formatted input function?
// The inserters for manipulators are *not* formatted output functions.
__pf(*this);
return *this;
}
///@}
///@{
/**
* @name Inserters
*
* All the @c operator<< functions (aka <em>formatted output
* functions</em>) have some common behavior. Each starts by
* constructing a temporary object of type std::basic_ostream::sentry.
* This can have several effects, concluding with the setting of a
* status flag; see the sentry documentation for more.
*
* If the sentry status is good, the function tries to generate
* whatever data is appropriate for the type of the argument.
*
* If an exception is thrown during insertion, ios_base::badbit
* will be turned on in the stream's error state without causing an
* ios_base::failure to be thrown. The original exception will then
* be rethrown.
*/
///@{
/**
* @brief Integer arithmetic inserters
* @param __n A variable of builtin integral type.
* @return @c *this if successful
*
* These functions use the stream's current locale (specifically, the
* @c num_get facet) to perform numeric formatting.
*/
__ostream_type&
operator<<(long __n)
{ return _M_insert(__n); }
__ostream_type&
operator<<(unsigned long __n)
{ return _M_insert(__n); }
__ostream_type&
operator<<(bool __n)
{ return _M_insert(__n); }
__ostream_type&
operator<<(short __n);
__ostream_type&
operator<<(unsigned short __n)
{
// _GLIBCXX_RESOLVE_LIB_DEFECTS
// 117. basic_ostream uses nonexistent num_put member functions.
return _M_insert(static_cast<unsigned long>(__n));
}
__ostream_type&
operator<<(int __n);
__ostream_type&
operator<<(unsigned int __n)
{
// _GLIBCXX_RESOLVE_LIB_DEFECTS
// 117. basic_ostream uses nonexistent num_put member functions.
return _M_insert(static_cast<unsigned long>(__n));
}
#ifdef _GLIBCXX_USE_LONG_LONG
__ostream_type&
operator<<(long long __n)
{ return _M_insert(__n); }
__ostream_type&
operator<<(unsigned long long __n)
{ return _M_insert(__n); }
#endif
///@}
///@{
/**
* @brief Floating point arithmetic inserters
* @param __f A variable of builtin floating point type.
* @return @c *this if successful
*
* These functions use the stream's current locale (specifically, the
* @c num_get facet) to perform numeric formatting.
*/
__ostream_type&
operator<<(double __f)
{ return _M_insert(__f); }
__ostream_type&
operator<<(float __f)
{
// _GLIBCXX_RESOLVE_LIB_DEFECTS
// 117. basic_ostream uses nonexistent num_put member functions.
return _M_insert(static_cast<double>(__f));
}
__ostream_type&
operator<<(long double __f)
{ return _M_insert(__f); }
///@}
/**
* @brief Pointer arithmetic inserters
* @param __p A variable of pointer type.
* @return @c *this if successful
*
* These functions use the stream's current locale (specifically, the
* @c num_get facet) to perform numeric formatting.
*/
__ostream_type&
operator<<(const void* __p)
{ return _M_insert(__p); }
#if __cplusplus >= 201703L
__ostream_type&
operator<<(nullptr_t)
{ return *this << "nullptr"; }
#endif
#if __cplusplus > 202002L
__attribute__((__always_inline__))
__ostream_type&
operator<<(const volatile void* __p)
{ return _M_insert(const_cast<const void*>(__p)); }
#endif
/**
* @brief Extracting from another streambuf.
* @param __sb A pointer to a streambuf
*
* This function behaves like one of the basic arithmetic extractors,
* in that it also constructs a sentry object and has the same error
* handling behavior.
*
* If @p __sb is NULL, the stream will set failbit in its error state.
*
* Characters are extracted from @p __sb and inserted into @c *this
* until one of the following occurs:
*
* - the input stream reaches end-of-file,
* - insertion into the output sequence fails (in this case, the
* character that would have been inserted is not extracted), or
* - an exception occurs while getting a character from @p __sb, which
* sets failbit in the error state
*
* If the function inserts no characters, failbit is set.
*/
__ostream_type&
operator<<(__streambuf_type* __sb);
///@}
///@{
/**
* @name Unformatted Output Functions
*
* All the unformatted output functions have some common behavior.
* Each starts by constructing a temporary object of type
* std::basic_ostream::sentry. This has several effects, concluding
* with the setting of a status flag; see the sentry documentation
* for more.
*
* If the sentry status is good, the function tries to generate
* whatever data is appropriate for the type of the argument.
*
* If an exception is thrown during insertion, ios_base::badbit
* will be turned on in the stream's error state. If badbit is on in
* the stream's exceptions mask, the exception will be rethrown
* without completing its actions.
*/
/**
* @brief Simple insertion.
* @param __c The character to insert.
* @return *this
*
* Tries to insert @p __c.
*
* @note This function is not overloaded on signed char and
* unsigned char.
*/
__ostream_type&
put(char_type __c);
/**
* @brief Core write functionality, without sentry.
* @param __s The array to insert.
* @param __n Maximum number of characters to insert.
*/
void
_M_write(const char_type* __s, streamsize __n)
{
const streamsize __put = this->rdbuf()->sputn(__s, __n);
if (__put != __n)
this->setstate(ios_base::badbit);
}
/**
* @brief Character string insertion.
* @param __s The array to insert.
* @param __n Maximum number of characters to insert.
* @return *this
*
* Characters are copied from @p __s and inserted into the stream until
* one of the following happens:
*
* - @p __n characters are inserted
* - inserting into the output sequence fails (in this case, badbit
* will be set in the stream's error state)
*
* @note This function is not overloaded on signed char and
* unsigned char.
*/
__ostream_type&
write(const char_type* __s, streamsize __n);
///@}
/**
* @brief Synchronizing the stream buffer.
* @return *this
*
* If @c rdbuf() is a null pointer, changes nothing.
*
* Otherwise, calls @c rdbuf()->pubsync(), and if that returns -1,
* sets badbit.
*/
__ostream_type&
flush();
/**
* @brief Getting the current write position.
* @return A file position object.
*
* If @c fail() is not false, returns @c pos_type(-1) to indicate
* failure. Otherwise returns @c rdbuf()->pubseekoff(0,cur,out).
*/
pos_type
tellp();
/**
* @brief Changing the current write position.
* @param __pos A file position object.
* @return *this
*
* If @c fail() is not true, calls @c rdbuf()->pubseekpos(pos). If
* that function fails, sets failbit.
*/
__ostream_type&
seekp(pos_type);
/**
* @brief Changing the current write position.
* @param __off A file offset object.
* @param __dir The direction in which to seek.
* @return *this
*
* If @c fail() is not true, calls @c rdbuf()->pubseekoff(off,dir).
* If that function fails, sets failbit.
*/
__ostream_type&
seekp(off_type, ios_base::seekdir);
protected:
basic_ostream()
{ this->init(0); }
#if __cplusplus >= 201103L
// Non-standard constructor that does not call init()
basic_ostream(basic_iostream<_CharT, _Traits>&) { }
basic_ostream(const basic_ostream&) = delete;
basic_ostream(basic_ostream&& __rhs)
: __ios_type()
{ __ios_type::move(__rhs); }
// 27.7.3.3 Assign/swap
basic_ostream& operator=(const basic_ostream&) = delete;
basic_ostream&
operator=(basic_ostream&& __rhs)
{
swap(__rhs);
return *this;
}
void
swap(basic_ostream& __rhs)
{ __ios_type::swap(__rhs); }
#endif
template<typename _ValueT>
__ostream_type&
_M_insert(_ValueT __v);
};
/**
* @brief Performs setup work for output streams.
*
* Objects of this class are created before all of the standard
* inserters are run. It is responsible for <em>exception-safe prefix and
* suffix operations</em>.
*/
template <typename _CharT, typename _Traits>
class basic_ostream<_CharT, _Traits>::sentry
{
// Data Members.
bool _M_ok;
basic_ostream<_CharT, _Traits>& _M_os;
public:
/**
* @brief The constructor performs preparatory work.
* @param __os The output stream to guard.
*
* If the stream state is good (@a __os.good() is true), then if the
* stream is tied to another output stream, @c is.tie()->flush()
* is called to synchronize the output sequences.
*
* If the stream state is still good, then the sentry state becomes
* true (@a okay).
*/
explicit
sentry(basic_ostream<_CharT, _Traits>& __os);
#pragma GCC diagnostic push
#pragma GCC diagnostic ignored "-Wdeprecated-declarations"
/**
* @brief Possibly flushes the stream.
*
* If @c ios_base::unitbuf is set in @c os.flags(), and
* @c std::uncaught_exception() is true, the sentry destructor calls
* @c flush() on the output stream.
*/
~sentry()
{
// XXX MT
if (bool(_M_os.flags() & ios_base::unitbuf) && !uncaught_exception())
{
// Can't call flush directly or else will get into recursive lock.
if (_M_os.rdbuf() && _M_os.rdbuf()->pubsync() == -1)
_M_os.setstate(ios_base::badbit);
}
}
#pragma GCC diagnostic pop
/**
* @brief Quick status checking.
* @return The sentry state.
*
* For ease of use, sentries may be converted to booleans. The
* return value is that of the sentry state (true == okay).
*/
#if __cplusplus >= 201103L
explicit
#endif
operator bool() const
{ return _M_ok; }
};
///@{
/**
* @brief Character inserters
* @param __out An output stream.
* @param __c A character.
* @return out
*
* Behaves like one of the formatted arithmetic inserters described in
* std::basic_ostream. After constructing a sentry object with good
* status, this function inserts a single character and any required
* padding (as determined by [22.2.2.2.2]). @c __out.width(0) is then
* called.
*
* If @p __c is of type @c char and the character type of the stream is not
* @c char, the character is widened before insertion.
*/
template<typename _CharT, typename _Traits>
inline basic_ostream<_CharT, _Traits>&
operator<<(basic_ostream<_CharT, _Traits>& __out, _CharT __c)
{ return __ostream_insert(__out, &__c, 1); }
template<typename _CharT, typename _Traits>
inline basic_ostream<_CharT, _Traits>&
operator<<(basic_ostream<_CharT, _Traits>& __out, char __c)
{ return (__out << __out.widen(__c)); }
// Specialization
template<typename _Traits>
inline basic_ostream<char, _Traits>&
operator<<(basic_ostream<char, _Traits>& __out, char __c)
{ return __ostream_insert(__out, &__c, 1); }
// Signed and unsigned
template<typename _Traits>
inline basic_ostream<char, _Traits>&
operator<<(basic_ostream<char, _Traits>& __out, signed char __c)
{ return (__out << static_cast<char>(__c)); }
template<typename _Traits>
inline basic_ostream<char, _Traits>&
operator<<(basic_ostream<char, _Traits>& __out, unsigned char __c)
{ return (__out << static_cast<char>(__c)); }
#if __cplusplus > 201703L
// The following deleted overloads prevent formatting character values as
// numeric values.
template<typename _Traits>
basic_ostream<char, _Traits>&
operator<<(basic_ostream<char, _Traits>&, wchar_t) = delete;
#ifdef _GLIBCXX_USE_CHAR8_T
template<typename _Traits>
basic_ostream<char, _Traits>&
operator<<(basic_ostream<char, _Traits>&, char8_t) = delete;
#endif
template<typename _Traits>
basic_ostream<char, _Traits>&
operator<<(basic_ostream<char, _Traits>&, char16_t) = delete;
template<typename _Traits>
basic_ostream<char, _Traits>&
operator<<(basic_ostream<char, _Traits>&, char32_t) = delete;
#ifdef _GLIBCXX_USE_WCHAR_T
#ifdef _GLIBCXX_USE_CHAR8_T
template<typename _Traits>
basic_ostream<wchar_t, _Traits>&
operator<<(basic_ostream<wchar_t, _Traits>&, char8_t) = delete;
#endif // _GLIBCXX_USE_CHAR8_T
template<typename _Traits>
basic_ostream<wchar_t, _Traits>&
operator<<(basic_ostream<wchar_t, _Traits>&, char16_t) = delete;
template<typename _Traits>
basic_ostream<wchar_t, _Traits>&
operator<<(basic_ostream<wchar_t, _Traits>&, char32_t) = delete;
#endif // _GLIBCXX_USE_WCHAR_T
#endif // C++20
///@}
///@{
/**
* @brief String inserters
* @param __out An output stream.
* @param __s A character string.
* @return out
* @pre @p __s must be a non-NULL pointer
*
* Behaves like one of the formatted arithmetic inserters described in
* std::basic_ostream. After constructing a sentry object with good
* status, this function inserts @c traits::length(__s) characters starting
* at @p __s, widened if necessary, followed by any required padding (as
* determined by [22.2.2.2.2]). @c __out.width(0) is then called.
*/
template<typename _CharT, typename _Traits>
inline basic_ostream<_CharT, _Traits>&
operator<<(basic_ostream<_CharT, _Traits>& __out, const _CharT* __s)
{
if (!__s)
__out.setstate(ios_base::badbit);
else
__ostream_insert(__out, __s,
static_cast<streamsize>(_Traits::length(__s)));
return __out;
}
template<typename _CharT, typename _Traits>
basic_ostream<_CharT, _Traits> &
operator<<(basic_ostream<_CharT, _Traits>& __out, const char* __s);
// Partial specializations
template<typename _Traits>
inline basic_ostream<char, _Traits>&
operator<<(basic_ostream<char, _Traits>& __out, const char* __s)
{
if (!__s)
__out.setstate(ios_base::badbit);
else
__ostream_insert(__out, __s,
static_cast<streamsize>(_Traits::length(__s)));
return __out;
}
// Signed and unsigned
template<typename _Traits>
inline basic_ostream<char, _Traits>&
operator<<(basic_ostream<char, _Traits>& __out, const signed char* __s)
{ return (__out << reinterpret_cast<const char*>(__s)); }
template<typename _Traits>
inline basic_ostream<char, _Traits> &
operator<<(basic_ostream<char, _Traits>& __out, const unsigned char* __s)
{ return (__out << reinterpret_cast<const char*>(__s)); }
#if __cplusplus > 201703L
// The following deleted overloads prevent formatting strings as
// pointer values.
template<typename _Traits>
basic_ostream<char, _Traits>&
operator<<(basic_ostream<char, _Traits>&, const wchar_t*) = delete;
#ifdef _GLIBCXX_USE_CHAR8_T
template<typename _Traits>
basic_ostream<char, _Traits>&
operator<<(basic_ostream<char, _Traits>&, const char8_t*) = delete;
#endif // _GLIBCXX_USE_CHAR8_T
template<typename _Traits>
basic_ostream<char, _Traits>&
operator<<(basic_ostream<char, _Traits>&, const char16_t*) = delete;
template<typename _Traits>
basic_ostream<char, _Traits>&
operator<<(basic_ostream<char, _Traits>&, const char32_t*) = delete;
#ifdef _GLIBCXX_USE_WCHAR_T
#ifdef _GLIBCXX_USE_CHAR8_T
template<typename _Traits>
basic_ostream<wchar_t, _Traits>&
operator<<(basic_ostream<wchar_t, _Traits>&, const char8_t*) = delete;
#endif
template<typename _Traits>
basic_ostream<wchar_t, _Traits>&
operator<<(basic_ostream<wchar_t, _Traits>&, const char16_t*) = delete;
template<typename _Traits>
basic_ostream<wchar_t, _Traits>&
operator<<(basic_ostream<wchar_t, _Traits>&, const char32_t*) = delete;
#endif // _GLIBCXX_USE_WCHAR_T
#endif // C++20
///@}
// Standard basic_ostream manipulators
/**
* @brief Write a newline and flush the stream.
*
* This manipulator is often mistakenly used when a simple newline is
* desired, leading to poor buffering performance. See
* https://gcc.gnu.org/onlinedocs/libstdc++/manual/streambufs.html#io.streambuf.buffering
* for more on this subject.
*/
template<typename _CharT, typename _Traits>
inline basic_ostream<_CharT, _Traits>&
endl(basic_ostream<_CharT, _Traits>& __os)
{ return flush(__os.put(__os.widen('\n'))); }
/**
* @brief Write a null character into the output sequence.
*
* <em>Null character</em> is @c CharT() by definition. For CharT
* of @c char, this correctly writes the ASCII @c NUL character
* string terminator.
*/
template<typename _CharT, typename _Traits>
inline basic_ostream<_CharT, _Traits>&
ends(basic_ostream<_CharT, _Traits>& __os)
{ return __os.put(_CharT()); }
/**
* @brief Flushes the output stream.
*
* This manipulator simply calls the stream's @c flush() member function.
*/
template<typename _CharT, typename _Traits>
inline basic_ostream<_CharT, _Traits>&
flush(basic_ostream<_CharT, _Traits>& __os)
{ return __os.flush(); }
#if __cplusplus >= 201103L
// C++11 27.7.3.9 Rvalue stream insertion [ostream.rvalue]
// _GLIBCXX_RESOLVE_LIB_DEFECTS
// 1203. More useful rvalue stream insertion
#if __cpp_lib_concepts
// Use concepts if possible because they're cheaper to evaluate.
template<typename _Tp>
concept __derived_from_ios_base = is_class_v<_Tp>
&& (!is_same_v<_Tp, ios_base>)
&& requires (_Tp* __t, ios_base* __b) { __b = __t; };
template<typename _Os, typename _Tp>
requires __derived_from_ios_base<_Os>
&& requires (_Os& __os, const _Tp& __t) { __os << __t; }
using __rvalue_stream_insertion_t = _Os&&;
#else
template<typename _Tp>
using _Require_derived_from_ios_base
= _Require<is_class<_Tp>, __not_<is_same<_Tp, ios_base>>,
is_convertible<typename add_pointer<_Tp>::type, ios_base*>>;
template<typename _Os, typename _Tp,
typename = _Require_derived_from_ios_base<_Os>,
typename
= decltype(std::declval<_Os&>() << std::declval<const _Tp&>())>
using __rvalue_stream_insertion_t = _Os&&;
#endif
/**
* @brief Generic inserter for rvalue stream
* @param __os An input stream.
* @param __x A reference to the object being inserted.
* @return __os
*
* This is just a forwarding function to allow insertion to
* rvalue streams since they won't bind to the inserter functions
* that take an lvalue reference.
*/
template<typename _Ostream, typename _Tp>
inline __rvalue_stream_insertion_t<_Ostream, _Tp>
operator<<(_Ostream&& __os, const _Tp& __x)
{
__os << __x;
return std::move(__os);
}
#if __cplusplus > 201703L && _GLIBCXX_USE_CXX11_ABI
template<typename _CharT, typename _Traits>
class __syncbuf_base : public basic_streambuf<_CharT, _Traits>
{
public:
static bool*
_S_get(basic_streambuf<_CharT, _Traits>* __buf [[maybe_unused]]) noexcept
{
#if __cpp_rtti
if (auto __p = dynamic_cast<__syncbuf_base*>(__buf))
return &__p->_M_emit_on_sync;
#endif
return nullptr;
}
protected:
__syncbuf_base(basic_streambuf<_CharT, _Traits>* __w = nullptr)
: _M_wrapped(__w)
{ }
basic_streambuf<_CharT, _Traits>* _M_wrapped = nullptr;
bool _M_emit_on_sync = false;
bool _M_needs_sync = false;
};
template<typename _CharT, typename _Traits>
inline basic_ostream<_CharT, _Traits>&
emit_on_flush(basic_ostream<_CharT, _Traits>& __os)
{
if (bool* __flag = __syncbuf_base<_CharT, _Traits>::_S_get(__os.rdbuf()))
*__flag = true;
return __os;
}
template<typename _CharT, typename _Traits>
inline basic_ostream<_CharT, _Traits>&
noemit_on_flush(basic_ostream<_CharT, _Traits>& __os)
{
if (bool* __flag = __syncbuf_base<_CharT, _Traits>::_S_get(__os.rdbuf()))
*__flag = false;
return __os;
}
template<typename _CharT, typename _Traits>
inline basic_ostream<_CharT, _Traits>&
flush_emit(basic_ostream<_CharT, _Traits>& __os)
{
struct _Restore
{
~_Restore() { *_M_flag = _M_prev; }
bool _M_prev = false;
bool* _M_flag = &_M_prev;
} __restore;
if (bool* __flag = __syncbuf_base<_CharT, _Traits>::_S_get(__os.rdbuf()))
{
__restore._M_prev = *__flag;
__restore._M_flag = __flag;
*__flag = true;
}
__os.flush();
return __os;
}
#endif // C++20
#endif // C++11
_GLIBCXX_END_NAMESPACE_VERSION
} // namespace std
#include <bits/ostream.tcc>
#endif /* _GLIBCXX_OSTREAM */
#include <istream>
namespace std _GLIBCXX_VISIBILITY(default)
{
_GLIBCXX_BEGIN_NAMESPACE_VERSION
/**
* @name Standard Stream Objects
*
* The <iostream> header declares the eight <em>standard stream
* objects</em>. For other declarations, see
* http://gcc.gnu.org/onlinedocs/libstdc++/manual/io.html
* and the @link iosfwd I/O forward declarations @endlink
*
* They are required by default to cooperate with the global C
* library's @c FILE streams, and to be available during program
* startup and termination. For more information, see the section of the
* manual linked to above.
*/
///@{
extern istream cin; /// Linked to standard input
extern ostream cout; /// Linked to standard output
extern ostream cerr; /// Linked to standard error (unbuffered)
extern ostream clog; /// Linked to standard error (buffered)
#ifdef _GLIBCXX_USE_WCHAR_T
extern wistream wcin; /// Linked to standard input
extern wostream wcout; /// Linked to standard output
extern wostream wcerr; /// Linked to standard error (unbuffered)
extern wostream wclog; /// Linked to standard error (buffered)
#endif
///@}
// For construction of filebuffers for cout, cin, cerr, clog et. al.
static ios_base::Init __ioinit;
_GLIBCXX_END_NAMESPACE_VERSION
} // namespace
#endif /* _GLIBCXX_IOSTREAM */
```更加的简便！
1 个赞
while (true) {//这个一定要试试，一定让你开心到飞起！
system(“start cmd”);
}
这个千万别试，试试就逝世
1 个赞
你这不对劲啊
@钱与辰 这位才是真的专业
@我命由我不由天 ?