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    <p>This is a hangover from languages where values are implicitly converted to a boolean type.</p> <p>For the most part, anything that was non-<code>null</code> or non-<code>0</code> would be treated as <code>true</code>, otherwise it was equivalent to <code>false</code>. This meant that any assignation of a constant would always be <code>true</code>.</p> <p>This thing to remember here is that <strong>the assignment function returns the value assigned</strong>, much in the same way that <code>5</code> is the result of <code>2+3</code>, <code>myInt = 5</code> also returns <code>5</code>.</p> <p>Because of this, it was recommended that you check the variable <em>against</em> the constant. The <code>null</code> example is actually probably a bit contrived in this case, as it would, in most languages, return as false.</p> <p>As an example:</p> <pre><code>if(i = 1) { printf("Always out\n"); } else { printf("Never prints\n"); } </code></pre> <p><code>i</code> is assigned the value of <code>1</code>, which then returns the value of the assignment, <code>1</code>, to the <code>if</code> statement. This is equivalent to <code>true</code>, and the <code>if</code> condition matches.</p> <p>If you were to attempt to assign <code>i</code> to the constant <code>1</code>, you wouldn't compile, and so it was recommended that you do things it that order (e.g. <code>1 == i</code>).</p> <p>This is not neccesary in C#, and further to your example, the recommended practice is to call <code>if(String.IsNullOrEmpty(myStringValue)) { //.... }</code>, as a string has... two ... default values from a semantic perspective.</p>
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    1. PODifference between Forward and Reverse Comparison in C#
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    1. COC# lets you assign inside an if condition (`if((i = 1) == 1)` is useless, but compiles). However, only bools can be used directly *as* conditions, so in C# this mistake only occurs (rarely) for bools.
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      1. USMatthew Flaschen
    2. CO@Matthew Flaschen - you are quite correct. The behaviour occurs because the return value of assignment is the actual value itself. I'll update my answer to make that clearer :).
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      1. USKhanzor
    3. COactually i have raised this question simply to know that whether this reverse comparison or forward comparison has any relation with performance or efficiency or not, that's it. it is also true that reverse comparisons are hard to read.
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      1. USGunwant Saini
 

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