*sigh* ...problem calculating percentage.
BlitzMax Forums/BlitzMax Beginners Area/*sigh* ...problem calculating percentage.
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| Sometimes I think I'm thick or something, but something that always causes me to grind to a halt is when I have to convert something to a percentage. I hope someone can save me some time before I spend too much time on it. :) So, assuming I have 2 vars. EnemiesKilled% ShotsFired% How do I calculate the hitrate of my shots as a percentage? (yeah, I know...basic algera, but like I said...I must be a bit thickheaded) :o) |
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(EnemiesKilled/ShotsFired)*100You may need to convert them to floats first though. (Float(EnemiesKilled)/Float(ShotsFired))*100 |
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| Ahh, perfect. Thanks Oddball. Silly how a simple thing like that give one problems. :) |
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Alternatively, without floats(EnemiesKilled*100)/ShotsFired |
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| If a single value in an equation is a float, then the entire equation will be evaluated as a float equation, so using a float value for the 100 (100.0 instead) would get the job done. (EnemiesKilled/ShotsFired)*100.0 |
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| That's not the way it works. The integer expression (EnemiesKilled/ShotsFired) would be evaluated first. The result would be converted to a float and multiplied by 100.0. For example (1/2)*100.0 is 0.0 rather than the 50.0 you might expect. |
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| Therefore, use: (EnemiesKilled*100.0) / ShotsFired |
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| That's not the way it works. I think Bill was probably thinking of a single value in an expression, rather than the whole equation. To borrow your example, all three of these: (1.0/2)*100.0 (1/2.0)*100.0 (1.0/2.0)*100.0 should give you the correct value. |
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| If you remember from school, B Brackets first O Orders (ie Powers and Square Roots, etc.) DM Division and Multiplication (left-to-right) AS Addition and Subtraction (left-to-right) Now the computer will religiously follow this for each operator, and will only increase accuracy when you say, so (Int/Int) * Float ____________ (1/2)*100.0 (INt)* Float = Float = 0 So even tho the answer is a float, the answer is wrong, because we loose accuracy in the division Int*Int/FLoat ____________ (1*100)/2.0 Int/Float ____________ 100/2.0 Float ____________ 50.0 So as Czar nearly had (EnemiesKilled*100)/Float (ShotsFired) IS an int multiplication and a float division, which looses no accuracy but is possibly faster than two float operations (In the Old Old days it would definitely be faster, I dont really know how efficient cpu/compilers are now adays) |
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