Question

I have been writing:

if(Class.HasSomething() == true/false) 
{
  // do somthing
}
else
{
  // do something else
}

but I’ve also seen people that do the opposite:

if(true/false == Class.HasSomething())
{
  // do somthing
}
else
{
  // do something else
}

Is there any advantage in doing one or the other in terms of performance and speed? I’m NOT talking about coding style here.

Answer 1

The second example is what I’ve heard called “Yoda conditions”; “False, this method’s return value must be”. It’s not the way you’d say it in English and so among English-speaking programmers it’s generally looked down on.

Performance-wise, there’s really no difference. The first example is generally better grammatically (and thus for readability), but given the name of your method the “grammar” involved (and the fact you’re comparing bool to bool) would make the equality check redundant anyway. So, for a true statement, I would simply write:

if(Class.HasSomething()) 
{
  // do somthing
}
else
{
  // do something else
}

This would be incrementally faster, as the if() block basically has a built-in equality comparison, so if you code if(Class.HasSomething() == true) the CLR will evaluate if((Class.HasSomething() == true) == true). But, we’re talking a gain of maybe a few clocks here (not milliseconds, not ticks, but clocks; the ones that happen 2 billion times a second in modern processors).

For a false condition, it’s a toss-up between using the not operator: if(!Class.HasSomething()) and using a comparison to false: if(Class.HasSomething() == false). The first is more concise, but it can be easy to miss that little exclamation point in a complex expression (especially since it occurs before the entire expression) and so I’d consider equating with false to ensure that the code is readable.