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Thread: What is best loop sequence?

  1. #1
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    Default What is best loop sequence?

    What is the most efficient code?


    Writen like this:


     if(vehicle.Branch.UWCompanyCode==typekey.UWCompanyCode.TC_CGIC){
     
        if( vehicle.CollisionAPRateGroup_CG==-1  and (vehicle.CostNew_CG==null or vehicle.CurrentValue_CG==null)){
     
          throwError(displaykey.Web.PolicyLine.Vehicle.NoVRGMessage)
        }
      }
     
      if(vehicle.Branch.UWCompanyCode==typekey.UWCompanyCode.TC_FA){
        if( vehicle.CollisionAPRateGroup_CG==-1  and vehicle.CurrentValue_CG==null){
     
          throwError(displaykey.Web.PolicyLine.Vehicle.NoVRGMessageFA)
        }
      }

    or like this one?

    if( vehicle.CollisionAPRateGroup_CG==-1){  
        if(vehicle.Branch.UWCompanyCode==typekey.UWCompanyCode.TC_CGIC and ( vehicle.CostNew_CG==null or vehicle.CurrentValue_CG==null)){ 
            throwError(displaykey.Web.PolicyLine.Vehicle.NoVRGMessage)
         }
        if(vehicle.Branch.UWCompanyCode==typekey.UWCompanyCode.TC_FA  and vehicle.CurrentValue_CG==null){  
              throwError(displaykey.Web.PolicyLine.Vehicle.NoVRGMessageFA)
        }
      }

    I think that is the same thing


  2. #2
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    Default Re: What is best loop sequence?

    What happened when you wrote an example program that measured the efficiency of each? What do you even mean by efficiency in this case?

    If you want help, you should provide a simpler example, without all those convoluted variable names.
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    Default Re: What is best loop sequence?

    Have you ever learned how to make a truth table?
    If you create a truth table, you should be able to find the most simplified logic.
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    Default Re: What is best loop sequence?

    It doesn't matter which is more efficient. For something as simple as conditional logic you would need to be executing it thousands of times per seconds *and* have the performance issues *and* perform extensive profiling *and* identify this logic as problematic to throughput before you even consider optimization.

    A more practical concern is correctness, readability and maintainability so the 'better' code is the one which is easier to understand so personally I think neither example hit's the mark. At a glance I can't easily tell which conditions which throw an exception and it even appears to have syntax errors.

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  6. #5
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    Default Re: What is best loop sequence?

    I'll try to simplify:

     
    if(vehicle.Company==G){
     
        if( vehicle.Collisions==-1  and (vehicle.Cost==null or vehicle.CurrentValue==null)){
     
          throwError(GMessage)
        }
      }
     
      if(vehicle.Company==F){
        if( vehicle.Collisions==-1  and vehicle.CurrentValue==null){
     
          throwError(FMessage)
        }
      }

    or
     
    if( vehicle.Collisions==-1){  
        if(vehicle.Company==G and ( vehicle.Cost==null or vehicle.CurrentValue==null)){ 
            throwError(GMessage)
         }
        if(vehicle.Company==F  and vehicle.CurrentValue==null){  
              throwError(FMessage)
        }
      }

    In the first one I have two if related to the vehicle company then nested in each I verify at the same time the 2 conditions to send an error: collissions -1 and if there are specific null fields.

    In the second one
    I verify in only one if first if collisions is -1 if yes I verify the conditions for the 2 companies G and F

    --- Update ---

    For each vehicle company we have diferent conditions to throw error and each company have their own error message:
    For G there are 2 fields that can not be null
    For F there are only one of them

    But for both collisions must be -1 to throw error

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    Default Re: What is best loop sequence?

    The "efficiency" of either case is entirely dependent on the context of your problem. Neither one is inherently better or worse.

    However, if your code is run in an environment where vehicle.Company is almost always G but vehicle.Collisions is almost never -1, then the first example will have to evaluate two boolean expressions much more often than your second if statement. The order of your if statements will also affect this type of "efficiency".

    Again, this is entirely dependent on your context, so it's going to be pretty impossible to give you a straight answer.
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    Default Re: What is best loop sequence?

    Thanks, I coded the first one and I was asked to change to the second by lead programmer (according to him that shoul simplify my code?!) I coded like that because as you said vehicle.Company is almost always G but vehicle.Collisions is almost never -1. And I wanted to be sure I was right thinking in the environment.

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    Default Re: What is best loop sequence?

    Quote Originally Posted by javaDruide View Post
    Thanks, I coded the first one and I was asked to change to the second by lead programmer (according to him that shoul simplify my code?!) I coded like that because as you said vehicle.Company is almost always G but vehicle.Collisions is almost never -1. And I wanted to be sure I was right thinking in the environment.
    You should have specified that in your original post then. I recommend asking the lead developer exactly why it simplifies the code, and explain to him your reasoning. It might just be a personal preference, or there might be a context you haven't explained (or aren't aware of yourself).
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    Default Re: What is best loop sequence?

    Presumably the vehicle.Company can't be both G and F? It makes more sense to use an if-elseif type control flow, or even just an if-else if there can't be any other values for Company. This makes more sense intuitively.

    Consider logically what each type of code is stating:

    Version 1 says if the Company is G, check for an error some way. Else, if the Company is F, check for an error some other way.

    Version 2 says if collision is -1, we probably have an error. Try to resolve if we do have an error by going into the details on what the Actual Company is.

    Both versions seem to be perfectly reasonable logic flows to me if you us an if/elseif, or even just an if/else. Otherwise I would would pick 2 as a clear winner for readability.

    Performance between the two is negligible if you're expecting an error to occur often, otherwise the second version theoretically is faster. As others have pointed out, though, unless you're throughput limited by this section of code, performance differences won't be noticeable.

  11. #10
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    Default Re: What is best loop sequence?

    The only "fully-true" outcome REQUIRES "vehicle.Collisions==-1" to be true in all scenarios. I agree with checking vehicle.Collisions==-1 first, since if that is false, evaluating vehicle.Company==G and vehicle.Company==F is unnecessary computations (it's not even noticeable computations in reality, but we are talking about simplification here).
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