QT Creator Unable to find STL outside of project, Bad install?

[egildon]

Hello,
I am new to C++ programming.
I was trying to write a simple hello world program.
I created a New File/C++ Source File...
Then I attempted to use includes from the STL

// Game1
//
// Demonstrates constants
 
#include <iostream>
using namespace std;
...

// Game1
//
// Demonstrates constants

#include <iostream>
using namespace std;
...

To copy to clipboard, switch view to plain text mode 

The: "include <iostream>" is always listed (highlighted) as an error. Why is this only happening here but not when I create a project?
Is there something wrong with my install?

Thanks in advance,

[anda_skoa]

What does "hightlighted" mean?
In an editor? Or do you get a build error?

Cheers,
_

[egildon]

Thanks for the reply!
:-)

When I hi-light the error it says :

iostream:No Such File or Directory
It will not allow me to build or run the code.
The complete program is here:

// Game1
//
// Demonstrates hello
 
#include <iostream>
using namespace std;
 
int main()
{
    std::cout << "Hello World!" << std::endl;
    return 0;
}

// Game1
//
// Demonstrates hello

#include <iostream>
using namespace std;

int main()
{
    std::cout << "Hello World!" << std::endl;
    return 0;
}

To copy to clipboard, switch view to plain text mode 

[anda_skoa]

What is the content of your project's .pro file?

Cheers,
_

[egildon]

What is the content of your project's .pro file?

Cheers,
_

Where do I find the .pro file?

[egildon]

What is the content of your project's .pro file?

Cheers,
_

There is no .pro file as I was attempting to write a single program and it is not part of a project. Is my thinking on this wrong?

[anda_skoa]

If you are not using qmake to generate the build files, are you using something else or are you manually writing a Makefile?
Or are you typing the compiler invocation manually in a shell?
You need to build the program somehow :-)

Cheers,
_