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copied!<p><strong>Most</strong> of the time, it does not matter whether you declare a variable inside or outside the loop; the rules of definite assignment ensure that it doesn't matter. In the debugger you might occasionally see old values (i.e. if you look at a variable in a breakpoint before it is assigned), but static-analysis proves that this won't impact executing code. The variables are never reset per loop, as there is demonstrably no need.</p> <p>At the IL level, **usually* the variable is declared just once for the method - the placement inside the loop is just a convenience for us programmers.</p> <p><strong>HOWEVER</strong> there is an important exception; any time a variable is captured, the scoping rules get more complex. For example (2 secs):</p> <pre><code> int value; for (int i = 0; i < 5; i++) { value = i; ThreadPool.QueueUserWorkItem(delegate { Console.WriteLine(value); }); } Console.ReadLine(); </code></pre> <p>Is <strong>very</strong> different to:</p> <pre><code> for (int i = 0; i < 5; i++) { int value = i; ThreadPool.QueueUserWorkItem(delegate { Console.WriteLine(value); }); } Console.ReadLine(); </code></pre> <p>As the "value" in the second example is <strong>truly</strong> per instance, since it is captured. This means that the first example might show (for example) "4 4 4 4 4", where-as the second example will show 0-5 (in any order) - i.e. "1 2 5 3 4".</p> <p>So: were captures involved in the original code? Anything with a lambda, an anonymous method, or a LINQ query would qualify.</p>

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