Re: basic function call an function under fstream

On Thu, Aug 27, 2026 at 11:56:51AM +0000, Jean-Christophe wrote:
> On Thu, 2026-08-27 at 07:22 +0200, [email protected] wrote:
> > On Wed, Aug 26, 2026 at 07:15:00PM +0000, Jean-Christophe wrote:
> > > hello,
> > > 
> > > i try to write an my_files.txt
> > > 
> > > and see the output on tty
> > 
> > As Dan Ritter said in this thread: you are calling fonction_deux:
> > 
> > > bool fonction_deux (){
> > > 	fstream my_file;
> > > 	my_file.open("my_file.txt", ios::out);
> > > 	if (!my_file) {
> > > 		cout << "File not created!";
> > 
> >         ...and here, you are writing to stdout (what you call "tt", I
> > think)
> > 
> > > 	}
> > > 	else {
> > > 		cout << "File created successfully!\n" << endl;
> > >  		cout << fonction_un() << endl;
> > > 
> > > 	my_file.close();
> > > 	}
> > > 	var_fonction_deux = true;
> > > 	return var_fonction_deux;
> > > }
> > 
> > and in all the other places too ("cout" writes to stdout).
> > If you want to write to your fstream my_file, which is
> > connected to "my_file.txt") you have to do something like
> > 
> >   my_file << "some text going to file" << endl;
> > 
> > (See https://www.w3schools.com/cpp/ref_fstream_fstream.asp for a more
> > complete example).
> 
> bool fonction_deux (){
> 	fstream MyFile("my_file.txt");
> 	if (!MyFile) {
> 		cout << "File not created!";
> 	}
> 	else {
> 		cout << "File created successfully!\n" << endl;
>  		 MyFile << fonction_un();
> 
> 		MyFile.close();
> 	}
> 	var_fonction_deux = true;
> 	return var_fonction_deux;
> }
> 
> I was inspired by the code, but I have the following compilation error:
> 
> $ g++ -std=c++23 test-fonction.cpp test-fonction.out 

Try: g++ -std=c++23 test-fonction.cpp -o test-fonction

(note the "-o" option and leaving out the ".out" suffix: by convention
binaries have no suffix, and the C++ compiler possibly tries to do
something different when seeing one, I don't know).

One more thing: what do you expect this line to do?

>  		 MyFile << fonction_un();

Cheers
-- 
t

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