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    <p>-1 is <code>get</code>'s way of saying you've reached the end of file. Compare it using the <code>std::char_traits&lt;char&gt;::eof()</code> (or <code>std::istream::traits_type::eof()</code>) - avoid -1, it's a magic number. (Although the other one is a bit verbose - you can always just call <code>istream::eof</code>)</p> <p>The EOF flag is only set once a read tries to read <em>past the end of the file</em>. If I have a 3 byte file, and I only read 3 bytes, EOF is <code>false</code>, because I've not tried to read past the end of the file yet. While this seems confusing for files, which typically know their size, EOF is not known until a read is attempted on some devices, such as pipes and network sockets.</p> <p>The second example works as <code>inf &gt;&gt; foo</code> will always return <code>inf</code>, with the side effect of attempt to read something and store it in <code>foo</code>. <code>inf</code>, in an <code>if</code> or <code>while</code>, will evaluate to <code>true</code> if the file is "good": no errors, no EOF. Thus, when a read fails, <code>inf</code> evaulates to <code>false</code>, and your loop properly aborts. However, take this common error:</p> <pre><code>while(!inf.eof()) // EOF is false here { inf &gt;&gt; x; // read fails, EOF becomes true, x is not set // use x // we use x, despite our read failing. } </code></pre> <p>However, this:</p> <pre><code>while(inf &gt;&gt; x) // Attempt read into x, return false if it fails { // will only be entered if read succeeded. } </code></pre> <p>Which is what we want.</p>
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    1. POHow does ifstream's eof() work?
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    1. USThanatos
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    1. POHow does ifstream's eof() work?
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    1. COThanks Thanatos. I think I get it now ;)
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    2. COProbably should not use >> instead of get(). Remember that the >> operator always skips proceeding white space before attempting to read the next value while get() reads every character one at a time.
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      1. USMartin York
    3. CO@Thanatos: Sorry to bother you but ... What about streams? You said that EOF is set when we try to read characters past the end of the file but **what happens when we try to `peek()` at the input stream `cin` when it has no characters?** The standard says that `traits::eof()` is called but **peek() seems to wait for an input** when I attempt to use it that way.
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