# How to implement armor? [closed]

I am a newbie in Python, I am very bad at math too and I need some help. Also close/move this post if you feel this isn't the right place for it.

``````Hero1 = 5000   # His HP is 5k.
Hero1dmg = 200 # damage output
``````

How can I subtract some value (let's say 20%) from Hero1's damage output?

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## closed as too localized by Byte56♦, jhocking, Jimmy, bummzack, Sean MiddleditchMar 7 '13 at 9:13

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Math is used extensively in programming and even more in game programming. You'll want to make sure you have a good understanding of the basics before continuing, otherwise you'll run into a lot of problems. Good luck! – Byte56 Mar 6 '13 at 22:44
Are we seriously teaching percentage math now? – jhocking Mar 6 '13 at 23:25
It's not that they're mad at you, they're debating whether or not this is the place to answer those kinds of questions. – Tetrad Mar 7 '13 at 0:23
It's OK to be bad at math. I think @jh wants to say that this is a game development site, not a math site and that most of this question is math. It's nothing personal - we're just trying to keep the site well organised. – Anko Mar 7 '13 at 0:30
@Anko I appreciate that, I really do, but instead of killing my hopes of ever being a programmer, he could have just said that he doesn't think this is the right place for that kind of question. Cheers – user27102 Mar 7 '13 at 0:32

A very basic formula would be:

``````damageAfterArmorCalc = damageAmt*(1-armorReductionPercent)
``````

`damageAmt` Is the original amount of damage to be done.

`armorReductionPercent` is the percent of damage the armor negates, this percentage should be a value from 0 to 1, so the 20% in your example would be `.2`. If we're doing 100 damage initially, we can look at some examples for what that does.

So what's happening here, if the armor does not negate any damage, then we get:

`100 * (1 - 0) = 100*1 = 100`

As you know, any number multiplied by one is still that number. Now if the armor negates 100% of damage, we would get

`100 * (1 - 1) = 100*0 = 0`

Since any number multiplied by zero is zero. Now we know it works for both extremes, how about the inbetween values? Say it negates 20% of damage as in your example. , we can see how that looks:

`100 * (1 - .2) = 100*.8 = 80`

We know that 20% of 100 is 20, and that 100 minus 20 is 80. So it looks like this works just fine.

I suggest you look into some basic math tutorials and get the basics down. Khan academy is a great resource for this.

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To subtract 20% off his damage output, multiply by .8 (20% = 0.2, so multiply by 1 - .2 = 0.8). That makes the new damage 160.

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