Practice Time: Declaring Variables and Constants

Let’s say you’re making a game with magic potions. Potions have different effects — they can heal players or hurt them. You would want to declare and initialize some constants and variables to store player health, and the amount of damage or healing caused by a potion.

But which should be constants, and which should be variables?

|  |  |
| --- | --- |
|  | var PlayerHealth: float = 100.0 |
|  | PotionDamageAmount: float = 20.0 |
|  | PotionHealAmount: float = 10.0 |

var PlayerHealth: float = 100.0 PotionDamageAmount: float = 20.0 PotionHealAmount: float = 10.0

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The variables and constants you're changing here won’t affect your Fortnite character's health, but you will learn how to do exactly that in a later lesson!

The player’s health will change during the game depending on what potions they use. When you think change, think variable.

On the other hand, it doesn’t make much sense to change the amount of damage or healing the potions do during the game, so those should be declared as constants.

If you write code to change the PlayerHealth variable now, you won’t be able to tell if it worked unless you print something to the log. To help with that, declare and initialize the string constant and string variable below. Remember to add the space between the end of the text and the last ".
```
|  |  |
| --- | --- |
|  | PlayerStatusText: string = "Player health now " |
|  | var EffectOnPlayerText: string = "damaged " |
```
PlayerStatusText: string = "Player health now " var EffectOnPlayerText: string = "damaged "

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Now you’re ready to change the player’s health. To change a variable’s value, you have to use the set keyword at the beginning of the expression. The PotionDamageAmount should be subtracted from PlayerHealth, so use the - operator.
```
     set PlayerHealth = PlayerHealth - PotionDamageAmount
```
set PlayerHealth = PlayerHealth - PotionDamageAmount

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After PlayerHealth changes, you want to see the proof! To do that, make the calls to Print() shown below.
```
|  |  |
| --- | --- |
|  | Print("The Player was {EffectOnPlayerText + ToString(PotionDamageAmount)}") |
|  | Print("{PlayerStatusText + ToString(PlayerHealth)}") |
```
Print("The Player was {EffectOnPlayerText + ToString(PotionDamageAmount)}") Print("{PlayerStatusText + ToString(PlayerHealth)}")

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It may seem like you are trying to do math with your strings but you are actually combining with the + operator. This is called concatenation. The ToString() function creates a string version of your float variable and constant so they can be used by Print().
Run this code now and you should see two new lines printed:
- The Player was damaged 20.0
- Player health now 80.00

Now on your own, try to do the same thing for PotionHealAmount.

Change PlayerHealth using the correct keyword and operator.
You’ll also need to change the EffectOnPlayerText variable so that it makes sense when printed.
Finally, you’ll need to print out how the player’s health was affected, and their current health. Try this by yourself first, but if you need help, look at the code below.
```
|  |  |
| --- | --- |
|  | set PlayerHealth = PlayerHealth + PotionHealAmount |
|  | set EffectOnPlayerText = "healed " |
|  | Print("The Player was {EffectOnPlayerText + ToString(PotionHealAmount)}") |
|  | Print("{PlayerStatusText + ToString(PlayerHealth)}") |
```
set PlayerHealth = PlayerHealth + PotionHealAmount set EffectOnPlayerText = "healed " Print("The Player was {EffectOnPlayerText + ToString(PotionHealAmount)}") Print("{PlayerStatusText + ToString(PlayerHealth)}")

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Complete Script

|  |  |
| --- | --- |
|  | using { /Fortnite.com/Devices } |
|  | using { /Verse.org/Simulation } |
|  |  |
|  | hello_world_device := class(creative_device): |
|  |  |
|  | # Runs when the device is started in a running game |
|  | OnBegin<override>()<suspends> : void = |
|  |  |
|  | PotionDamageAmount : float = 20.0 |
|  | PotionHealAmount : float = 10.0 |
|  | var  PlayerHealth : float = 100.0 |
|  |  |
|  | PlayerStatusText : string = "Player health now " |
|  | var EffectOnPlayerText: string = "damaged " |
|  |  |
|  | set PlayerHealth = PlayerHealth - PotionDamageAmount |
|  | Print("The Player was {EffectOnPlayerText + ToString(PotionDamageAmount)}") |
|  | Print("{PlayerStatusText + ToString(PlayerHealth)}") |
|  |  |
|  | set PlayerHealth = PlayerHealth + PotionHealAmount |
|  | set EffectOnPlayerText = "healed " |
|  | Print("The Player was {EffectOnPlayerText + ToString(PotionHealAmount)}") |
|  | Print("{PlayerStatusText + ToString(PlayerHealth)}") |

using { /Fortnite.com/Devices } using { /Verse.org/Simulation } hello_world_device := class(creative_device):

Runs when the device is started in a running game

OnBegin<override>()<suspends> : void = PotionDamageAmount : float = 20.0 PotionHealAmount : float = 10.0 var PlayerHealth : float = 100.0 PlayerStatusText : string = "Player health now " var EffectOnPlayerText: string = "damaged " set PlayerHealth = PlayerHealth - PotionDamageAmount Print("The Player was {EffectOnPlayerText + ToString(PotionDamageAmount)}") Print("{PlayerStatusText + ToString(PlayerHealth)}") set PlayerHealth = PlayerHealth + PotionHealAmount set EffectOnPlayerText = "healed " Print("The Player was {EffectOnPlayerText + ToString(PotionHealAmount)}") Print("{PlayerStatusText + ToString(PlayerHealth)}")

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Next Lesson

[

Lesson 4: Writing Simple Code

Practice is the key to competence. Practice writing more code!](/docs/documentation/en-us/fortnite/basics-of-writing-code-4-writing-simple-code-in-verse.md)