关于c++的问题请教高手

[jinger7281]

最近两天突然对c++感兴趣，但是刚上来就碰了壁，希望c++高手帮小弟解决这个问题，这是我QQ号希望高手能加我详细帮我（验证信息c++
）
这是我的c++程序
#include <iostream.h>
int main(){
cout<<"hello world";
}
这是编译的时候提示
pinger@pinger-desktop:~$ g++ hello.cpp
hello.cpp:1:22: error: iostream.h: 没有该文件或目录
hello.cpp: In function ‘int main()’:
hello.cpp:3: 错误： ‘cout’在此作用域中尚未声明
看完之后我感觉头文件不对，就在include里边找这个头文件，终于找到了（在include/c++/4.3有个iostream）并做了如下修改
#include <c++／4.3／iostream>
int main(){
cout<<"hello world";
}
然后出现以下提示
pinger@pinger-desktop:~$ g++ hello.cpp
hello.cpp: In function ‘int main()’:
hello.cpp:3: 错误： ‘cout’在此作用域中尚未声明
这是iostream文件下的内容：
// Standard iostream objects -*- C++ -*-

// Copyright (C) 1997, 1998, 1999, 2001, 2002, 2005
// 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 2, 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.

// You should have received a copy of the GNU General Public License
// along with this library; see the file COPYING. If not, write to
// the Free Software Foundation, 51 Franklin Street, Fifth Floor,
// Boston, MA 02110-1301, USA.

// As a special exception, you may use this file as part of a free software
// library without restriction. Specifically, if other files instantiate
// templates or use macros or inline functions from this file, or you compile
// this file and link it with other files to produce an executable, this
// file does not by itself cause the resulting executable to be covered by
// the GNU General Public License. This exception does not however
// invalidate any other reasons why the executable file might be covered by
// the GNU General Public License.

/** @file 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>

_GLIBCXX_BEGIN_NAMESPACE(std)

/**
* @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++ ... to.html#10 and the
* @link s27_2_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 HOWTO 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

#endif /* _GLIBCXX_IOSTREAM */
希望高手能加我QQ给我详细解释以下，感激不尽！

[cnkilior]

#include <iostream.h> ----->>>>#include <iostream>

[jinger7281]

换成＃include <iostream>还是出现这样的提示
pinger@pinger-desktop:~$ g++ hello.cpp
hello.cpp: In function ‘int main()’:
hello.cpp:3: 错误： ‘cout’在此作用域中尚未声明

[cnkilior]

喂给你吃好了

代码： 全选

#include <iostream>
int main(){
using namespace std;
cout<<"hello world";
}

[jinger7281]

问题解决了
喂给额吃的大哥，有空解释一下这个入门级的东东是怎么回事吗？谢谢了

[BigSnake.NET]

iostream.h 应该是可以的， 不知道为什么你的会 file not found

[Chine]

LZ看的是哪个年代的C＋＋？呵呵～

[jinger7281]

唉！我还以为经典书能学点东西！奶奶的害苦我了！刚才去google了一下，知道是怎么回事了！谢谢各位大哥帮忙

[lerosua]

还真是喂了啊~~

[casa]

......

在#include <iostream.h>的下面一行加一句：
using namespace std;

因为cout是在std这个命名空间里面定义的~你没调用，当然说cout有问题啦~

还有，#include <iostream.h>是C的风格
C++的风格就是用#include <iostream>

其实随便哪种写法效果都一样的

[Whistler]

最新的 gcc 已经像 VS.net 2005 一样，把 iostream.h 之类的取消了。。。

[BigSnake.NET]

......

在#include <iostream.h>的下面一行加一句：
using namespace std;

因为cout是在std这个命名空间里面定义的~你没调用，当然说cout有问题啦~

还有，#include <iostream.h>是C的风格
C++的风格就是用#include <iostream>

其实随便哪种写法效果都一样的

iostream.h 是向后兼容的玩意, 没有命名空间的版本