I am working on the 'driver' part of my programing assignment and i keep getting this absurd error:
error C2065: 'cout' : undeclared identifier
I have even tried using the std::cout but I get another error that says:
IntelliSense: namespace "std" has no member "cout"
When I have declared using namespace std, included iostream and I even tried to use ostream
#include <iostream>
using namespace std;
int main () {
cout << "hey" << endl;
return 0;
}
I'm using Visual Studio 2010 and running Windows 7. All of the .h files have using namespace std and include iostream and ostream.
In Visual Studio you must #include "stdafx.h" and be the first include of the cpp file. For instance:
These will not work.
#include <iostream>
using namespace std;
int main () {
cout << "hey" << endl;
return 0;
}
#include <iostream>
#include "stdafx.h"
using namespace std;
int main () {
cout << "hey" << endl;
return 0;
}
This will do.
#include "stdafx.h"
#include <iostream>
using namespace std;
int main () {
cout << "hey" << endl;
return 0;
}
Here is a great answer on what the stdafx.h header does.
write this code, it works perfectly..
#include "stdafx.h"
#include <iostream>
using namespace std;
int main()
{
cout<<"Hello World!";
return 0;
}
I had same problem on Visual Studio C++ 2010. It's easy to fix. Above the main() function just replace the standard include lines with this below but with the pound symbol in front of the includes.
# include "stdafx.h"
# include <iostream>
using namespace std;
The include "stdafx.h" is ok
But you can't use cout unless you have included using namespace std
If you have not included namespace std you have to write std::cout instead of simple cout
If the only file you include is iostream and it still says undefined, then maybe iostream doesn't contain what it's supposed to. Is it possible that you have an empty file coincidentally named "iostream" in your project?
I have seen that if you use
#include <iostream.h>
then you will get the problem.
If you use
#include <iostream>
(notice - without the .h)
then you will not get the problem you mentioned.
If you started a project requiring the #include "stdafx.h" line, put it first.
I've seen similar things happen when I was using the .c file extension with C++ code. Other than that, I'd have to agree with everyone about a buggy installation. Does it work if you try to compile the project with an earlier release of VS? Try VC++ Express 2008. Its free on msdn.
Such a silly solution in my case:
// Example a
#include <iostream>
#include "stdafx.h"
The above was odered as per example a, when I changed it to resemble example b below...
// Example b
#include "stdafx.h"
#include <iostream>
My code compiled like a charm. Try it, guaranteed to work.
The code below compiles and runs properly for me using gcc. Try copy/pasting this and see if it works.
#include <iostream>
using namespace std;
int bob (int a) { cout << "hey" << endl; return 0; };
int main () {
int a = 1;
bob(a);
return 0;
}
I have VS2010, Beta 1 and Beta 2 (one on my work machine and one at home), and I've used std plenty without issues. Try typing:
std::
And see if Intellisense gives you anything. If it gives you the usual stuff (abort, abs, acos, etc.), except for cout, well then, that is quite a puzzler. Definitely look into your C++ headers in that case.
Beyond that, I would just add to make sure you're running a regular, empty project (not CLR, where Intellisense is crippled), and that you've actually attempted to build the project at least once. As I mentioned in a comment, VS2010 parses files once you've added an include; it could be that something stuck the parser and it didn't "find" cout right away. (In which case, try restarting VS maybe?)
Take the code
#include <iostream>
using namespace std;
out of your .cpp file, create a header file and put this in the .h file. Then add
#include "whatever your header file is named.h"
at the top of your .cpp code. Then run it again.
I had the same issue when starting a ms c++ 2010 project from scratch - I removed all of the header files generated by ms and but used:
#include "stdafx.h"
#include <iostream>
using namespace std;
int main() {
cout << "hey" << endl;
return 0;
}
I had to include stdafx.h as it caused an error not having it in.
Try it, it will work. I checked it in Windows XP, Visual Studio 2010 Express.
#include "stdafx.h"
#include <iostream>
using namespace std;
void main( )
{
int i = 0;
cout << "Enter a number: ";
cin >> i;
}
before you begin this program get rid of all the code and do a simple hello world inside of main. Only include iostream and using namespace std;.
Little by little add to it to find your issue.
cout << "hi" << endl;
Are you sure it's compiling as C++? Check your file name (it should end in .cpp). Check your project settings.
There's simply nothing wrong with your program, and cout is in namespace std. Your installation of VS 2010 Beta 2 is defective, and I don't think it's just your installation.
I don't think VS 2010 is ready for C++ yet. The standard "Hello, World" program didn't work on Beta 1. I just tried creating a test Win32 console application, and the generated test.cpp file didn't have a main() function.
I've got a really, really bad feeling about VS 2010.
When you created your project, you did not set 'use precompiled headers' correctly. Change it in properties->C/C++->precompiled headers.
In Visual studio use all your header filer below "stdafx.h".
Just use printf!
Include stdio.h in your stdafx.h header file for printf.
Include the std library by inserting the following line at the top of your code:
using namespace std;
is normally stored in the C:\Program Files\Microsoft Visual Studio 8\VC\include folder. First check if it is still there. Then choose Tools + Options, Projects and Solutions, VC++ Directories, choose "Include files" in the "Show Directories for" combobox and double-check that $(VCInstallDir)include is on top of the list.
I ran across this error after just having installed vs 2010 and just trying to get a nearly identical program to work.
I've done vanilla C coding on unix-style boxes before, decided I'd play with this a bit myself.
The first program I tried was:
#include "stdafx.h"
int _tmain(int argc, _TCHAR* argv[])
{
cout << "Hello World!";
return 0;
}
The big thing to notice here... if you've EVER done any C coding,
int _tmain(int argc, _TCHAR* argv[])
Looks weird. it should be:
int main( int argc, char ** argv )
In my case I just changed the program to:
#include <iostream>
using namespace std;
int main()
{
cout << "Hello world from VS 2010!\n";
return 0;
}
And it worked fine.
Note: Use CTRL + F5 so that the console window sticks around so you can see the results.
I came here because I had the same problem, but when I did #include "stdafx.h" it said it did not find that file.
What did the trick for me was: #include <algorithm>.
I use Microsoft Visual Studio 2008.
These are the things that you can use then, incl. 'count': Link
Had this problem, when header files declared "using namespace std;", seems to be confusing for GNU compiler;
anyway is bad style!
Solution was providing std::cout ... in headers and moving "using namespace std" to the implementation file.
In VS2017, stdafx.h seems to be replaced by pch.h see this article,
so use:
#include "pch.h"
#include <iostream>
using namespace std;
int main() {
cout << "Enter 2 numbers:" << endl;
It was the compiler - I'm now using Eclipse Galileo and the program works like a wonder
Related
I try to build a simple piece of code in Visual Studio, but the building process gets entangled in an infinite loop.
The code is simple:
// test.cpp : Defines the entry point for the console application.
//
#include <iostream.h>
using namespace std;
int main(void)
{
cout << "Hi." << endl;
return 0;
}
Any idea what is going on?
Thanks.
spot several things:
not sure what's in 'stdafx.h'
#include < iostream >
std::cout, std::endl (unless using namespace std; somewhere)
Build works fine for me, though.
Visual Studio is not recognising my #include 'Header.h' file. I have created the file in the Header Files in solution explorer and also tried manually pointing to the file. What I don't understand is, until yesterday there was absolutely no problem. Therefore, a simple cout doesn't work.
#include 'Header.h';
int main()
{
cout << "hi";
return 0;
}
#include "Header.h"
#include <iostream>
using namespace std;
int main()
{
cout << "hi";
return 0;
}
Not that Header.h is used in anyway, this is still the correct syntax.
You need #include <iostream> to be able to use cout.
You've got syntax errors in your #include preprocessor directive. Replace single with double quotes and drop the semicolon:
#include "Header.h"
Found the problem : I had to go to properties bar and change "Included In Folder" value to true from false.
I have been trying to debug this problem for a while and quite honestly, I just can't see what I'm doing wrong.
Why is there a syntax error?
#include <iostream>;
#include <time.h>;
#include <stdio.h>;
#include <stdlib.h>;
using namespace std;
class Problem3 {
public:
bool isPrime(long double num) {
srand(time(NULL));
return 0;
}
};
The error I'm getting is,
"Function 'srand' could not be resolved."
I'm well aware now that I don't need the semi-colons after 'include' statements
I'm using Eclipse CDT along with MinGW as my compiler
How I resolved the problem:
It had to do with the MinGW compiler I was using. Switching over to Visual Studio solved the problem.
; at the end of the #include directives are the problem in your code. #include directives don't need (wrong to place indeed) semicolons at the end unlike C++ statements.
[Warning] extra tokens at end of #include directive [enabled by default]
It seems any character after > in the directive causes this error/warning.
#include<iostream>a //error
Change to this:
#include <iostream>
#include <time.h>
#include <stdio.h>
#include <stdlib.h>
using namespace std;
class Problem3 {
public:
bool isPrime(long double num) {
srand(time(NULL));
return 0;
}
};
int main(){
cout<<"Hello Main";
}
EDIT:
Regarding the linker issue:
One suggestion is C++ expects types to be explicitly casted between types (more than C). So, use a cast to convert time_t which is returned by the time to unsigned int which is the input parameter type of srand. (And of course this might not be the problem with linker error)
Instead of using stdlib.h, try using <cstdlib>, try if it helps. Because it uses namespace.
Apart from that, I have seen this snippet here. Use that pattern if it helps.
#include <cstdlib>
#include <iostream>
#include <ctime>
using namespace std;
int main()
{
srand(time(0)); //use current time as seed for random generator
int random_variable = rand();
cout << "Random value on [0 " << RAND_MAX << "]: "
<< random_variable << '\n';
}
there is already question in SO check if that helps Eclipse Method could not be resolved in a simple program C++
Never use time() to initialize srand()..
EDIT:
Now it seems many people got this kind of problem. I found a question How do I fix Eclipse CDT Error “Function 'isdigit' could not be resolved. He is facing the same problem. The asker suggested a work around to this in his question edit.
Quoted from that question:
I now believe this to be a Code Analysis problem. A better solution is
to edit the Code Analysis options to make "Function could not be
resolved" be a warning instead of an error. That way you can see the
warnings in Problems view, but continue to work. If the function is
REALLY missing, the compiler will tell you! I also have a new theory,
that the problem is with the Code Analyzer following symlinks, because
all of the "missing" functions are in symlinked include files. Would
love any input on this theory.
Hope that points to solve the problem.
; should not be there after #include.
#include <iostream>
#include <time.h>
#include <stdio.h>
#include <stdlib.h>
#include files shoule not end with ;
Hi I am just starting to learn C++. I bought this big C++ for Dummies book and have been going through it. Its been really interesting so far but now I am stuck. I have been googling this problem, but to no avail. I am using I am using codeblocks 10.05 with GNU GCC.
I keep getting an error that says:
In function 'main':
undefined reference to 'SafeCracker(int)'
The code isn't complicated. I am just new and am extremely frustrated. I don't want to skip over this part; I want to know what is going on.
Main:
#include <iostream>
#include "safestuff.h"
using namespace std;
int main()
{
cout << "Surprise, surprise!" << endl;
cout << "The combination is (once again)" << endl;
cout << SafeCracker(12) << endl;
return 0;
}
Function:
#include <iostream>
using namespace std;
string SafeCracker(int SafeID)
{
return "13-26-16";
}
Header:
using namespace std;
#ifndef SAFESTUFF_H_INCLUDED
#define SAFESTUFF_H_INCLUDED
string SafeCracker(int SafeID);
#endif // SAFESTUFF_H_INCLUDED
You are not compiling the second file you listed along with the first one. Try compiling directly with gcc to understand this.
assuming your files are named:
main.cpp
SafeCracker.cpp
safestuff.h
This is what you are doing
gcc main.cpp
While you should be doing this
gcc main.cpp SafeCracker.cpp
Also, SafeCracker.cpp should be including the header file as well, just for clarity. Any reasons why you have them separated?
On another note, from seeing Daniel Hu's answer, <iostream> is automatically including <string> for you. You should not depend on this functionality, and should instead include <string> in each file that uses strings.
(From comment below)
You're probably trying to build your main.cpp as a stand-alone file. This will leave SafeCracker.cpp uncompiled. What you need is create a project in Codeblocks and add all three files to it (both *.cpp files as well as the *.h file).
I think it's because you did not #include <string>
C++ has to import the string library to use strings or else everything is treated as char arrays.
I'm doing something wrong, I know. I can't quite figure out how to
link two .cpp files together through a header file. The calling
method can't see the other source.
I'm using Code::Blocks as an IDE with MinGW.
Any help would be greatly appreciated. It would be even more
appreciated if you could show the fixed source, link in the reply to a
pastebin page with it.
/***********************************main.cpp***********************************/
#include <iostream>
using namespace std;
#include "test.h"
int main()
{
printTest(); //can't see printTest, defined in test.cpp
return 0;
};
/***********************************test.h***********************************/
#ifndef TEST_H_INCLUDED
#define TEST_H_INCLUDED
void printTest();
#endif // TEST_H_INCLUDED
/***********************************test.cpp***********************************/
#include "test.h"
void printTest()
{
cout << "Hello world!" << endl;
};
You might find this code blocks wiki helpful. It looks like Code blocks uses a managed build system so if you add the file to the project properly then it should know to compile it and link in the object file that results.
And just to be more explicit about some other comments, when you use "using namespace std;" the namespace is only brought into scope for the file where the using statement is located. That is why others are telling you to explicitly specify the std:: namespace. You could also bring all of the std namespace into scope in the test.cpp file. Many people consider this a bad habit to get into. It's generally better to bring into scope just what you need via
using std::cout;
using std::endl;
Finally, remember that std::endl adds a new line AND flushes the buffer, it's not a good replacement for a new line character in all cases.
In test.cpp replace cout << "Hello world!" << endl;
by std::cout << "Hello world!" << std::endl;
sanket answer’s seems incomplete to me.
You need to add #include <iostream> in your test.cpp so that the compiler knows what "cout" is.
As sanket stated, you should use std::cout and std::endl in test.cpp.