When typing the following line:
QwtPointSeriesData* myData = new QwtPointSeriesData;
It says to me that identifier is undefined. But I have typed the following includes in which, it was mentioned that it cannot open those opens pource files.
#include <qwt_plot_curve.h>
#include "qwt_series_data.h"
Any ideas how to solve and find out how to get them?
To answer my question :
It seems that I was having an very old version of QWT!
Related
I'm writing C++ in VSCode. The nullptr is marked by red cursive line and showing identifier "nullptr" is undefined. Though, I can run this code perfectly with code-runner extension. But how do I get rid of this false alert in VSCode?
As is pointed in the comments, in the project folder, just find .vscode/c_cpp_properties.json file and change the C++ version to C11. Problem fixed.
I had same issue previously. I tried only adding these two lines:
#include <iostream>
#using std::cout; using std::endl; using std::cin;
warning disappeared
I am getting the following error when using the identifier DDRB:
identifier "DDRB" is undefined
But, when I click “go to definition”, the IDE does shows that it can find them. The code also compiles without any problem. I was using VScode first and setting intellisense to "tag parser" did work, but it also got rid of the error checking. So, I switched over to Visual Studio, but the issue remains. In both cases I included the AVR library.
I have googled quite a bit and found some solutions, but most were outdated or did not work. What can I do to resolve this issue?
"minimal reproducible example:"
#include <avr\io.h>
int main() {
DDRB |= (1 << DD3);
}
I can reproduce same issue in VS2017, and this one can be resolved by adding the #define __AVR_ATmega32U4__ above the #include <avr\io.h> like this:
#define __AVR_ATmega32U4__
#include <iostream>
#include <avr/io.h>
int main()
{
DDRB |= (1 << DD3);
}
After adding the macro definition, VS Intellisense option can recognize them well and the issue goes away. More details refer to Kissiel's reply. Thanks to him!
If you don't want to paste this definition into almost every file:
press f1
find C/C++; Edit configurations (UI)
paste your mcu name in Defines section e.g __AVR_ATmega32U4__
It worked for me in vs code.
I just tried to compile my C++ code and an error appears when I try to do so.
The error appears on line 9
Here are the versions of the gcc and g++ and such
Any help would be appreciated.
Edit:
I am also including Movie.h:
And also Movie.cpp:
https://puu.sh/vb53G/9e9abd1832.png (I was not able to include more than 3 images due to restrictions)
Firstly, in your Movie.h file, you have not included the string header file correctly. It should be:
#include <string> // without the .h extension
error: 'string' does not name a type
Secondly, you have forgotten to add the closing parenthesis of the constructor function of class "Movie". I am assuming that you have added this now, after the edit
As for the marking done by your compiler, you may find the following StackOverflow post helpful:
StackOverflow Post: Unresolved inclusion iostream.
The link is for the Eclipse IDE, but you can find a similar solution for your own IDE (I cannot tell which one you have).
The line under the #include is just a warning (I'm not sure why).
However, the errors are from the "Movie" class:
1. add "using namespace std" on the top of this class.
2. close the parenthesis on the constructor of 'Movie'.
The error messages are fairly clear:
'string' does not name a type
That is, the compiler is unaware of the type string because either:
you have not #include <string> in Movie.h
or you have, but have not brought it into your namespace with a using namespace std;
although why not just refer to it as std::string?
You are missing
#include <string>
So, I have this question. Why does cout throws
error C2065: 'cout' : undeclared identifier
I am using Visual Studio 2012 as an IDE and I am writing a school project. I have everything done except an example file. So I am trying to write something on the screen like this:
#include "iostream"
#include "stdafx.h"
using namespace std;
int main()
{
cout<<"example";
return 0;
}
So the problem is with cout... printf works fine, but I want to use cout.
EDIT:
I've changed "" to <> but it is not helping. Also I am using this code only for example... This is not the whole project.
stdafx.h shall be the first include directive in your source file.
Switch files and convert the second include to <>, as other suggested.
#include "stdafx.h"
#include <iostream>
See this post for more information.
First of all:
#include <iostream>
instead of #include "iostream"
Secondly, it is generally considered bad practice to write using namespace std;, even though most courses start with that. It is better to only use what you actually need, in your case:
using std::cout;
#include "iostream"
should be
#include <iostream>
Quoting from this post:difference-between-iostream-and-iostream-quotes-in-include
By courtesy of #Jerry Coffin's answer:
When you use < >, the compiler only looks in the system-designated directory/directories (e.g., whatever you've set in the include environment variable) for the header.
When you use " ", the compiler looks in the local directory first, and if that fails, re-searches just like you'd used < >. Technically, (i.e., according to the standard) that doesn't have to be the "local" directory, but that's how it works in essentially every compiler of which I'm aware).
EDIT:
However, the root cause is that stdafx.h is a precompiled header. Visual C++ will not compile anything before the #include "stdafx.h" in the source file, unless the compile option /Yu'stdafx.h' is unchecked (by default); it assumes all code in the source up to and including that line is already compiled. However, it is still better to use <> with iostream not to confuse reader of the code.
If you use #include <iostream> with the <> instead of "" then it should work. Right now, the compiler doesn't know where to find the iostream library.
Also, you might want to change cout<<"example"; to cout<<"example"<<endl; for a new line so that it formats correctly.
Came across this issue while trying to build a Dynamic Linked Library. Make sure that instead of the #include stdafx.h you specify the following include on the first line of your .cpp file:
#include "pch.h"
This should also be the case for VS2017 or earlier.
This error also occurred in the Visual Studio 2017 IDE. Moving stdafx.h to the top solved the error.
For more on stdafx.h, see What's the use for "stdafx.h" in Visual Studio?
I didn't find anything like this when I searched for it. I'm trying to make a simple gstreamer app based on code I found in another stack overflow thread. Whenever I try to compile it by going to the directory with command prompt and entering cl cppgstreamer.cc. Initially, the only include was #include <gstreamermm.h>, which gives me
cppgstreamer.cc(1) : fatal error C1083: Cannot open include file: 'gstreamermm.h
': No such file or directory
Even when I put cppgstreamer.cc into the same directory as gstreamermm.h. I then tried changing the include to
#include "C:\Users\MY_NAME\Documents\gstreamer c++\gstreamermm-0.10.10.2\gstreamer\gstreamermm.h"
with MY_NAME being replaced by my name.
This seems to work, but then it tries to do the includes in the gstreamermm.h, and they are in #include <file.h> form, so I get another fatal error C1083,except this time with init.h, or when I changed that, error.h. And they have dependencies. Is there a way that I can get my compiler to like the #include <file.h> syntax? I really don't want to go through the file and change every #include <file.h> to #include "file.h".
Sorry if this is a dumb question. I'm new to C++, although I've worked with C in the past.
I am using Microsoft Visual C++ Express 2010. Any help would be appreciated. Thanks!
You need to add the directory containing gstreamermm.h to include path. I don't have visual c++ here to check, but it's in somewhere in project properties under C/C++ .