Weird thing with fstream

[gukn9700]

When I used fstream to handle a file, I met with a very weird thing:

#include <fstream>
#include <iostream>

using namespace std;

int main()
{
fstream outfile;

outfile.open("t est.txt", ios_base::in | ios_base::out);
if (!outfile)
{
cout << "open file fail!\n";
return -1;
}

//display original text
char ch;
while (outfile.get(ch ))
{
cout << ch;
}
cout << '\n';
outfile.clear() ; //clear eofbit

//seek to end of the text
outfile.seekp(0 , ios_base::end);
//get input from the user and append it to outfile
while (cin.get(ch))
{
outfile.put(ch) ;
}

outfile.close() ;
return 0;
}

the content of test.txt is:

This is a text
only for test.

But after I ran the program, it turned out to be:

ThThis is a text
only for test.
abcdefg

The "abcdefg" was the input. But, where did the additional "Th" come
from?

What's wrong with my program?

Compiler: gcc3.2.3
System: Windows2000
Compile option: -ansi -Wall

[Jim Fischer]

Re: Weird thing with fstream

gukn9700 wrote:[color=blue]
> When I used fstream to handle a file, I met with a very weird thing:
>
> [code snipped]
>
> the content of test.txt is:
>
> This is a text
> only for test.
>
> But after I ran the program, it turned out to be:
>
> ThThis is a text
> only for test.
> abcdefg
>
> The "abcdefg" was the input. But, where did the additional "Th" come
> from?
>
> What's wrong with my program?
>
> Compiler: gcc3.2.3
> System: Windows2000
> Compile option: -ansi -Wall[/color]

Hmmm... That's odd. Your program looks OK to me, and it works as
expected when compiled with G++ 3.3 on a Red Hat 9 Linux box.

Just out of curiosity, what happens if you specify the 'binary' mode
flag when the program opens the text file, i.e.,

outfile.open ("test.txt", ios_base::out | ios_base::binar y);

--
Jim

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