C++: Write to an existing file? -

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this question has answer here:

in c++, need write existing file , keep previous content there.

this have done:

std::ofstream logging;  logging.open(filename);  logging << "hello\n";  logging.close();

but previous text overwritten (gone). did wrong?

thanks in advance.

logging.open(filename, std::ios_base::app);

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