因此,我是C ++的完整入门者,并且我正在尝试制作一个简单的“ Hello world”程序进行作业。我的代码如下:
#include "stdafx.h"
#include <iostream>
using namespace std;
int main() {
cout<<"hello world!";
return 0;
}
由于某些原因,VS2017在cout
处引发错误,表示未定义。我已经阅读了一些有关旧帖子的内容,并在#include "stdafx.h
中进行了添加,以查看是否可以按照旧建议解决该问题,但这仍然给我带来了错误。有什么想法吗?
编辑:
还是一个完整的菜鸟,但是当我搜索它时会出现多个版本的stdafx.h,这看起来像是“主要”一个:
// stdafx.h : include file for standard system include files,
// or project specific include files that are used frequently,
// but are changed infrequently
#pragma once
#ifndef STRICT
#define STRICT
#endif
#include "targetver.h"
[!if SERVICE_APP]
#define _ATL_FREE_THREADED
[!else]
#define _ATL_APARTMENT_THREADED
[!endif]
#define _ATL_NO_AUTOMATIC_NAMESPACE
#define _ATL_CSTRING_EXPLICIT_CONSTRUCTORS // some CString constructors will be explicit
[!if PREVIEW_HANDLER || THUMBNAIL_HANDLER || SEARCH_HANDLER]
#ifdef _MANAGED
#error File type handlers cannot be built as managed assemblies. Set the Common Language Runtime options to no CLR support in project properties.
#endif
#ifndef _UNICODE
#error File type handlers must be built Unicode. Set the Character Set option to Unicode in project properties.
#endif
#define SHARED_HANDLERS
[!endif]
[!if SUPPORT_MFC]
#include <afxwin.h>
#include <afxext.h>
#include <afxole.h>
#include <afxodlgs.h>
#include <afxrich.h>
#include <afxhtml.h>
#include <afxcview.h>
#include <afxwinappex.h>
#include <afxframewndex.h>
#include <afxmdiframewndex.h>
#ifndef _AFX_NO_OLE_SUPPORT
#include <afxdisp.h> // MFC Automation classes
#endif // _AFX_NO_OLE_SUPPORT
[!endif]
[!if SUPPORT_COMPLUS]
#include <comsvcs.h>
[!endif]
#define ATL_NO_ASSERT_ON_DESTROY_NONEXISTENT_WINDOW
#include "resource.h"
#include <atlbase.h>
#include <atlcom.h>
#include <atlctl.h>
答案 0 :(得分:5)
error C2065: 'cout': undeclared identifier
是缺少#include <iostream>
的结果。第一个原因可能是stdafx.h
的内容。您提供的一个,我不确定它与您的main.cpp
/项目有什么关系。让我们从一个新项目开始: ... VS2017 IDE:创建一个新项目,ConsoleApplication项目类型,并用您的函数替换main()
函数。
一个VS2017 IDE(15.8.2)全新的ConsoleApplication项目:ConsoleApplication1
// ConsoleApplication1.cpp : Defines the entry point for the console application.
//
#include "stdafx.h"
#include <iostream>
using namespace std;
int main() {
cout << "hello world!";
return 0;
}
stdafx.h:(由IDE生成)
// stdafx.h : include file for standard system include files,
// or project specific include files that are used frequently, but
// are changed infrequently
//
#pragma once
#include "targetver.h"
// TODO: reference additional headers your program requires here
stdafx.cpp:(由IDE生成)
// stdafx.cpp : source file that includes just the standard includes
// ConsoleApplication1.pch will be the pre-compiled header
// stdafx.obj will contain the pre-compiled type information
#include "stdafx.h"
// TODO: reference any additional headers you need in STDAFX.H
// and not in this file
targetver.h:(由IDE生成)
#pragma once
// Including SDKDDKVer.h defines the highest available Windows platform.
// If you wish to build your application for a previous Windows platform, include WinSDKVer.h and
// set the _WIN32_WINNT macro to the platform you wish to support before including SDKDDKVer.h.
#include <SDKDDKVer.h>
**这段代码可以完美运行。 **
-
“搜索时会出现stdafx.h的多个版本” -您是什么意思?在您的项目中?在网上?您不能只从互联网上获取一个stdafx.h
。 stdafx.h
内容是针对每个项目量身定制的,并非通用。例如,我在上面提供的是IDE默认的新ConsoleApplication项目stdafx.h
。您可以根据项目需要将其添加到文件中。