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Basics of Writing Code 4 Practice Time in Verse

Return to your magic potion code from the last exercise. You will want to run the healing code when the player drinks a healing potion, and the damage code when they drink a damaging potion.

First You Write Some Code ...

  1. Sounds like you'll have to answer a question about the type of potion, so you can create a new variable to keep track of that, a string called PotionType.

         var PotionType: string = "heal"

    var PotionType: string = "heal"

    Copy full snippet(1 line long)

  2. Now you can ask if the variable PotionType is equal to another string. When you ask if PotionType is equal to "heal", the answer will be yes. The healing code would then run.

    |  |  |
| --- | --- |
|  | if (PotionType = "heal"): |
|  | set PlayerHealth = PlayerHealth + PotionHealAmount |

    if (PotionType = "heal"): set PlayerHealth = PlayerHealth + PotionHealAmount

    Copy full snippet(2 lines long)

  3. Now write a similar if expression for the damage code.

    |  |  |
| --- | --- |
|  | if (PotionType = "damage"): |
|  | set PlayerHealth = PlayerHealth - PotionDamageAmount |

    if (PotionType = "damage"): set PlayerHealth = PlayerHealth - PotionDamageAmount

    Copy full snippet(2 lines long)

    But wait! There’s a problem with the healing code!

    Nothing here stops a player from continuing to raise their health with potions. It’s a good idea to limit this, and now you can with if!

  4. First, declare a new constant of type float. Call it MaxHealth and set it to 100.0.

         MaxHealth: float = 100.0

    MaxHealth: float = 100.0

    Copy full snippet(1 line long)

    If the value of PlayerHealth would go over the value of MaxHealth when a player drinks the healing potion, you'll need to set PlayerHealth to MaxHealth.

    |  |  |
| --- | --- |
|  | # Code to run if player drinks a healing potion |
|  | # If the player's health would not exceed MaxHealth if they were healed, |
|  | # heal them the full amount |
|  | if (PotionType = "heal" and (PlayerHealth + PotionHealAmount) < MaxHealth): |
|  | set PlayerHealth = PlayerHealth + PotionHealAmount |
|  | else: |
|  | set PlayerHealth = MaxHealth |

    Code to run if player drinks a healing potion

    If the player's health would not exceed MaxHealth if they were healed,

    heal them the full amount

    if (PotionType = "heal" and (PlayerHealth + PotionHealAmount) < MaxHealth): set PlayerHealth = PlayerHealth + PotionHealAmount else: set PlayerHealth = MaxHealth

    Copy full snippet(7 lines long)

    Notice that the code above has an and to ask if the PotionType is equal to "heal" and if the PlayerHealth + PotionAmount is less than MaxHealth. Both of these conditions need to succeed for the PlayerHealth to be increased by the PotionHealAmount.

    It may not be clear to someone reading this code that it’s meant to prevent PlayerHealth from exceeding MaxHealth. That’s where code comments come in. Note the three lines of comments above the actual code.

  5. The damage code works, but it can be improved with the use of if … else if … else. If a player drinks a damage potion that would make PlayerHealth 0.0 or less, we want to set PlayerHealth to 1.0 instead. If PlayerHealth is already 1.0, then we set it to 0.0. This teaches the player the potion is harmful without being too punishing.

    |  |  |
| --- | --- |
|  | # Code to run if player drinks a damaging potion |
|  | # Don't eliminate the player if their health is above MinHealth but below PotionDamageAmount |
|  | # If they are already equal to or below MinHealth, eliminate them |
|  | if (PotionType = "damage" and PlayerHealth &gt; PotionDamageAmount): |
|  | set PlayerHealth = PlayerHealth - PotionDamageAmount |
|  | else if (PlayerHealth &gt; MinHealth): |
|  | # Give player one more chance if their health is low |
|  | set PlayerHealth = 1.0 |
|  | else: |
|  | set PlayerHealth = 0.0 |

    Code to run if player drinks a damaging potion

    Don't eliminate the player if their health is above MinHealth but below PotionDamageAmount

    If they are already equal to or below MinHealth, eliminate them

    if (PotionType = "damage" and PlayerHealth &gt; PotionDamageAmount): set PlayerHealth = PlayerHealth - PotionDamageAmount else if (PlayerHealth &gt; MinHealth):

    Give player one more chance if their health is low

    set PlayerHealth = 1.0 else: set PlayerHealth = 0.0

    Copy full snippet(10 lines long)

... Then You Find the Bug

Below you’ll find all of the code from this exercise, with some Print() function calls added for testing. Try running this code. Feel free to change the Print() calls to whatever you like. With the PotionType variable initialized to “heal”, you can expect that only the healing code will run.

But wait, there’s a bug!

Run the code below and see if you can find it.

|  |  |
| --- | --- |
|  | MaxHealth: float = 100.0 |
|  | MinHealth: float = 1.0 |
|  | var PotionType: string = "heal" |
|  |  |
|  | # Code to run if player drinks a healing potion |
|  | # If the player's health would not exceed MaxHealth if they were healed, |
|  | # heal them the full amount |
|  | if (PotionType = "heal" and (PlayerHealth + PotionHealAmount) < MaxHealth): |
|  | set PlayerHealth = PlayerHealth + PotionHealAmount |
|  | Print ("Full heal") |
|  | else: |
|  | # else, set PlayerHealth the MaxHealth |
|  | set PlayerHealth = MaxHealth |
|  | Print("PlayerHealth too high for full heal") |
|  |  |
|  | # Code to run if player drinks a damaging potion |
|  | # Don't eliminate the player if their health is above MinHealth but below PotionDamageAmount |
|  | # If they are already equal to or below MinHealth, eliminate them |
|  | if (PotionType = "damage" and PlayerHealth > PotionDamageAmount): |
|  | set PlayerHealth = PlayerHealth - PotionDamageAmount |
|  | Print("Full damage") |
|  | else if (PlayerHealth > MinHealth): |
|  | # Give player one more chance if their health is low |
|  | set PlayerHealth = 1.0 |
|  | Print("PlayerHealth set to 1.0") |
|  | else: |
|  | # Eliminate player |
|  | set PlayerHealth = 0.0 |
|  | Print("Player eliminated!") |

MaxHealth: float = 100.0 MinHealth: float = 1.0 var PotionType: string = "heal"

Code to run if player drinks a healing potion

If the player's health would not exceed MaxHealth if they were healed,

heal them the full amount

if (PotionType = "heal" and (PlayerHealth + PotionHealAmount) < MaxHealth): set PlayerHealth = PlayerHealth + PotionHealAmount Print ("Full heal") else:

else, set PlayerHealth the MaxHealth

set PlayerHealth = MaxHealth Print("PlayerHealth too high for full heal")

Code to run if player drinks a damaging potion

Don't eliminate the player if their health is above MinHealth but below PotionDamageAmount

If they are already equal to or below MinHealth, eliminate them

if (PotionType = "damage" and PlayerHealth > PotionDamageAmount): set PlayerHealth = PlayerHealth - PotionDamageAmount Print("Full damage") else if (PlayerHealth > MinHealth):

Give player one more chance if their health is low

set PlayerHealth = 1.0 Print("PlayerHealth set to 1.0") else:

Eliminate player

set PlayerHealth = 0.0 Print("Player eliminated!")

Collapse code Copy full snippet(29 lines long)

If PotionType is set to heal, only the healing code should run. However, the if … else if … if expressions in the damage code are still being executed. This means that if PlayerHealth is greater than MinHealth, the PlayerHealth will get set to 1.0. This is not what you want, but you can fix it by nesting the other checks within if expressions that only check PotionType.

|  |  |
| --- | --- |
|  | # Code to run if player drinks a healing potion |
|  | # If the player's health would not exceed MaxHealth if they were healed, |
|  | # heal them the full amount |
|  | if (PotionType = "heal"): |
|  | if ((PlayerHealth + PotionHealAmount) < MaxHealth): |
|  | set PlayerHealth = PlayerHealth + PotionHealAmount |
|  | Print ("Full heal") |
|  | else: |
|  | # set PlayerHealth the MaxHealth |
|  | set PlayerHealth = MaxHealth |
|  | Print("PlayerHealth too high for full heal") |
|  |  |
|  | # Code to run if player drinks a damaging potion |
|  | # Don't eliminate the player if their health is above MinHealth but below PotionDamageAmount |
|  | # If they are already equal to or below MinHealth, eliminate them |
|  | if (PotionType = "damage"): |
|  | if ((PlayerHealth > PotionDamageAmount)): |
|  | set PlayerHealth = PlayerHealth - PotionDamageAmount |
|  | Print("Full damage") |
|  | else if (PlayerHealth > MinHealth): |
|  | # Give player one more chance if their health is low |
|  | set PlayerHealth = 1.0 |
|  | Print("PlayerHealth set to 1.0") |
|  | else: |
|  | # Eliminate player |
|  | set PlayerHealth = 0.0 |
|  | Print("Player eliminated!") |

Code to run if player drinks a healing potion

If the player's health would not exceed MaxHealth if they were healed,

heal them the full amount

if (PotionType = "heal"): if ((PlayerHealth + PotionHealAmount) < MaxHealth): set PlayerHealth = PlayerHealth + PotionHealAmount Print ("Full heal") else:

set PlayerHealth the MaxHealth

set PlayerHealth = MaxHealth Print("PlayerHealth too high for full heal")

Code to run if player drinks a damaging potion

Don't eliminate the player if their health is above MinHealth but below PotionDamageAmount

If they are already equal to or below MinHealth, eliminate them

if (PotionType = "damage"): if ((PlayerHealth > PotionDamageAmount)): set PlayerHealth = PlayerHealth - PotionDamageAmount Print("Full damage") else if (PlayerHealth > MinHealth):

Give player one more chance if their health is low

set PlayerHealth = 1.0 Print("PlayerHealth set to 1.0") else:

Eliminate player

set PlayerHealth = 0.0 Print("Player eliminated!")

Collapse code Copy full snippet(27 lines long)

Now, only the block of code indented under one of the if expressions that check PotionType will run. Try this code with PotionType set to "damage" as well.

Whew! That’s a lot of code changes, but you did it!

Take a break, drink some po- er… water, and come back when you’re ready for the next lesson.

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 = |
|  |  |
|  | MaxHealth : float = 100.0 |
|  | MinHealth : float = 1.0 |
|  | var PotionType: string = "heal" |
|  |  |
|  | set PlayerHealth = 80.0 |
|  |  |
|  | # Code to run if player drinks a healing potion |
|  | # If the player's health would not exceed MaxHealth if they were healed, |
|  | # heal them the full amount |
|  | if (PotionType = "heal"): |
|  | if ((PlayerHealth + PotionHealAmount) < MaxHealth): |
|  | set PlayerHealth = PlayerHealth + PotionHealAmount |
|  | Print ("Full heal") |
|  | else: |
|  | # else, set PlayerHealth the MaxHealth |
|  | set PlayerHealth = MaxHealth |
|  | Print("PlayerHealth too high for full heal") |
|  |  |
|  | # Code to run if player drinks a damaging potion |
|  | # Don't eliminate the player if their health is above MinHealth but below PotionDamageAmount |
|  | # If they are already equal to or below MinHealth, eliminate them |
|  | if (PotionType = "damage"): |
|  | if ((PlayerHealth > PotionDamageAmount)): |
|  | set PlayerHealth = PlayerHealth - PotionDamageAmount |
|  | Print("Full damage") |
|  | else if (PlayerHealth > MinHealth): |
|  | # Give player one more chance if their health is low |
|  | set PlayerHealth = 1.0 |
|  | Print("PlayerHealth set to 1.0") |
|  | else: |
|  | set PlayerHealth = 0.0 |
|  | Print("Player eliminated!") |
|  |  |
|  | Print("PlayerHealth now {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 = MaxHealth : float = 100.0 MinHealth : float = 1.0 var PotionType: string = "heal" set PlayerHealth = 80.0

Code to run if player drinks a healing potion

If the player's health would not exceed MaxHealth if they were healed,

heal them the full amount

if (PotionType = "heal"): if ((PlayerHealth + PotionHealAmount) < MaxHealth): set PlayerHealth = PlayerHealth + PotionHealAmount Print ("Full heal") else:

else, set PlayerHealth the MaxHealth

set PlayerHealth = MaxHealth Print("PlayerHealth too high for full heal")

Code to run if player drinks a damaging potion

Don't eliminate the player if their health is above MinHealth but below PotionDamageAmount

If they are already equal to or below MinHealth, eliminate them

if (PotionType = "damage"): if ((PlayerHealth > PotionDamageAmount)): set PlayerHealth = PlayerHealth - PotionDamageAmount Print("Full damage") else if (PlayerHealth > MinHealth):

Give player one more chance if their health is low

set PlayerHealth = 1.0 Print("PlayerHealth set to 1.0") else: set PlayerHealth = 0.0 Print("Player eliminated!") Print("PlayerHealth now {PlayerHealth}")

Collapse code Copy full snippet(42 lines long)

Next Lesson

  • [Lesson 5: Calling Functions

    Lesson 5: Calling Functions

    Why do the same work twice if you don't have to?](/docs/documentation/en-us/fortnite/basics-of-writing-code-5-calling-functions-in-verse.md)