Question

Hi which one is faster

            int a = 100;
        //First Way
        if (a != 100)
        {
            //Do something when a is not equal to 100
        }
        else
        {
            //Do something when a is equal to 100
        }

        //Second Way
        if (a == 100)
        {
            //Do something when a is equal to 100

        }
        else
        {
            //Do something when a is not equal to 100
        }

I thinks second way is faster , but I am curious to Know how NOT EQUAL (!=) operator is solved . Is it like first it implements equal(==) operation and then the result is negated like !(a==100) ? Any help will be highly appericiated.

Answer 1

There is no difference between the two whatsoever. For an int, it all boils down to one of two assembly instructions on x86:

• je – Jump if equal
• jne – Jump it not equal

These, or any of the jxx instructions all take the same amount of time.

See also my other answer related to your question.

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Since you really seem to care, I suggest you test it yourself. Write up two loops, one that uses == and one that uses !=. Then time them with a System.Diagnostics.Stopwatch, by wrapping them in calls to Start() and Stop(). Then compare. With a high enough number of iterations through the loop (to minimize other timing errors like context switches, interrupts, etc.) you will see no difference.