copying a file, ifstream+ofstream?

This is a discussion on copying a file, ifstream+ofstream? within the C++ Programming forums, part of the General Programming Boards category; I decided I wanted to learn some file i/o and started by copying a file...specifically an image png file.. which ...

  1. #1
    Registered User
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    Aug 2005
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    copying a file, ifstream+ofstream?

    I decided I wanted to learn some file i/o and started by copying a file...specifically an image png file.. which ended up working but am wondering if this is the best/correct way to be doing this and if I could possibly run into problems ?

    I used this code for a simple 2 liner of text file and it worked, then to my surprise it worked on an image without complain though.

    is there a more clever way than this, that i am not seeing?
    Code:
    void copy_file(string srcf , const char *destf)
    {
    	ofstream dest;
    	ifstream src;
    	src.open(srcf.c_str());
    	dest.open(destf);
    	string words;
    	while(getline(src,words))
    	{
    		dest << words << endl;
    	}
    }
    and as well, I read that theres a close method.. are file automatically closed anyway? I mean my file was created .. it must have been closed by itself anyway.

  2. #2
    and the Hat of Guessing tabstop's Avatar
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    Streams are closed when the variable goes out of scope (i.e., as part of the destructor). On some architectures (e.g. Windows if I recall correctly) some binary files may get mangled by getline (a \r\n pair would get translated into just \n). You can open a file in C++ in binary mode by
    Code:
    src.open(srcf.c_str(), ios::binary);

  3. #3
    Registered User
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    Oct 2008
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    1,262
    This should work:
    Code:
    dest << src.rdbuf();
    At least... I GUESS it's standard compliant, but someone else should probably tell us whether I'm right.

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