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copy doesn't work

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why the output i get is different when i use copy()? It's like copy() doesn't write to the file anything :(
set<int> answer;
.....

    ofstream out ( "OUTPUT.TXT" );
    out << answer.size() << endl;

   for( set<int>::iterator it = answer.begin(); it != answer.end(); ++it )
        out << *it << endl;
    //copy( answer.begin(), answer.end(), ostream_iterator<int>( out, "\n" ) );
//if i use copy() insread of the for loop it doesn't work :(



what's the problem? thx

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This might sound stupid but... Are you flushing the stream after you write to it?

copy( answer.begin(), answer.end(), ostream_iterator<int>( out, "\n" ) );
out.flush();

I suspect if you do that you will see something in the file.

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It should be.

I don't know, it might have to do with some other part of the code... I just made this simple test program here:


#include <iostream>
#include <set>

#include <time.h>

using namespace std;

void main() {
srand((unsigned int) time(NULL));

set<int> answer;
set<int>::iterator iter;

for (int i = 0; i < 10; i++) {
answer.insert(rand() % 255);
}

cout << "For loop:" << endl;

for (iter = answer.begin(); iter != answer.end(); iter++) {
cout << (*iter) << endl;
}

cout << endl << endl;

cout << "copy():" << endl;

copy(answer.begin(), answer.end(), ostream_iterator<int>(cout, "\n"));
}




Works perfectly fine, and seems to be equivalent to what you posted.

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Why not try:

copy( answer.begin(), answer.end(), ostream_iterator<int>( cout, "\n" ) );

And see what it spits out onto the console?

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it works now! i dont' know what happened before but now it works, without any modifications! It seems in my code i had
ostream_iterator<int>( cout, "\n" )
instead of
ostream_iterator<int>( out, "\n" )

...

thx guys and sorry for being an idiot :)

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