problem with file

[Paolo]

Why does this stupid code read twice last number??? Tnx

#include <stdlib.h>
#include <iostream>
#include <fstream>

using namespace std;

int main ( )
{

int number;
ofstream testfile ( "test.txt" , ios::app);

cout<<"Insert a number, ctrl+z to end"<<endl;

while(cin>>number){
testfile<<number<<endl;
cout<<"Insert a number, ctrl + z to end"<<endl;
}

testfile.close();


cout<<"Reading number(s)from file..."<<endl;

ifstream testfile2 ("test.txt" , ios::in );

while(!testfile2.eof()){
testfile2>>number;
cout<<number<<endl;
}



system ("pause");
}

 

[Victor Bazarov]

Why does this stupid code read twice last number??? Tnx

IIRC, there was a bug in Microsoft's I/O code. Try looking in the
archives for "read last line twice" or something like that.

[...]

V

 

[Dietmar Kuehl]

Why does this stupid code read twice last number???

Probably because it is, as you said, stupid! Of course,
you might find out the yourself as this question was
answered quite frequently but here is key problem anyway:
The stream does not know a priori whether an operation
will fail. Thus, you should always check the stream after
your operation: you did it right in the first loop, you
did it wrong in the second.

 

[Paolo]

Il Fri, 14 Jan 2005 11:11:47 -0500, Victor Bazarov

IIRC, there was a bug in Microsoft's I/O code. Try looking in the
archives for "read last line twice" or something like that.

Thank you, I solved

 

[Paolo]

Il 14 Jan 2005 08:15:37 -0800, "Dietmar Kuehl"

Probably because it is, as you said, stupid! Of course,
you might find out the yourself as this question was
answered quite frequently but here is key problem anyway:
The stream does not know a priori whether an operation
will fail. Thus, you should always check the stream after
your operation: you did it right in the first loop, you
did it wrong in the second.

Thank u, solved in this way:

while(testfile2>>number) {
cout<<number<<endl;
}

 

[David Harmon]

On Fri, 14 Jan 2005 17:04:11 +0100 in comp.lang.c++, Paolo

Why does this stupid code read twice last number??? Tnx ....
while(!testfile2.eof()){

This issue is covered in Marshall Cline's C++ FAQ. See the topic
"[15.5] Why does my input seem to process past the end of file?" It is
always good to check the FAQ before posting. You can get the FAQ at:
http://www.parashift.com/c++-faq-lite/

 

[Paolo]

Il Sat, 15 Jan 2005 19:03:36 GMT, David Harmon <[email protected]> ha
scritto:

This issue is covered in Marshall Cline's C++ FAQ. See the topic
"[15.5] Why does my input seem to process past the end of file?" It is
always good to check the FAQ before posting. You can get the FAQ at:
http://www.parashift.com/c++-faq-lite/

Thank you, these FAQs are very useful
I don't know about them (how to get them in particular), sorry again!