iostream是什么

iostream是信息流，控制输入输出

iostream怎么用

#include

using namespace std;

int a;

int main(){

//输入

cin>>a;

//输出

cout<

return 0;

}

iostream缺失

在C:\Program Files (x86)\Dev-Cpp\MinGW64\lib\gcc\x86_64-w64-mingw32\4.9.2\include\c++添加一个叫iostream的文件（不加后缀名），用c++打开后粘贴如下代码后编译即可修复

// Standard iostream objects -*- C++ -*-

// Copyright (C) 1997-2014 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

// .

/** @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

#include

#include

namespace std _GLIBCXX_VISIBILITY(default)

{

_GLIBCXX_BEGIN_NAMESPACE_VERSION

/**

* @name Standard Stream Objects

*

* The <iostream> header declares the eight standard stream

* objects. 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 */