Old DND Character

10 Points

Instructions

For a game of Dungeons & Dragons (DND), each player starts by generating a character they can play with. This character has, among other things, six abilities:

strength,
dexterity,
constitution,
intelligence,
wisdom,
charisma.

These six abilities have scores that are determined randomly. You do this by rolling four 6-sided dice and record the sum of the largest three dice. You do this six times, once for each ability.

Your character's initial hitpoints are 10 + your character's constitution modifier. You find your character's constitution modifier by subtracting 10 from your character's constitution, divide by 2 and round down.

Advanced Concept

If you prefer mathematical notation, the modifier is defined as

\operatorname{modifier}\left(\text{constitution}\right) = \left\lfloor\frac{\text{constitution} - 10}{2}\right\rfloor

and the hitpoints are defined as

\operatorname{HP}\left(\text{constitution}\right) = 10 + \operatorname{modifier}\left(\text{constitution}\right)

For example, the six throws of four dice may look like:

5, 3, 1, 6: You discard the 1 and sum 5 + 3 + 6 = 14, which you assign to strength.
3, 2, 5, 3: You discard the 2 and sum 3 + 5 + 3 = 11, which you assign to dexterity.
1, 1, 1, 1: You discard the 1 and sum 1 + 1 + 1 = 3, which you assign to constitution.
2, 1, 6, 6: You discard the 1 and sum 2 + 6 + 6 = 14, which you assign to intelligence.
3, 5, 3, 4: You discard the 3 and sum 5 + 3 + 4 = 12, which you assign to wisdom.
6, 6, 6, 6: You discard the 6 and sum 6 + 6 + 6 = 18, which you assign to charisma.

Because the constitution is 3, the constitution modifier is -4, and the hitpoints are 10 - 4 = 6.

1. Generate valid ability values

Implement a function ability() that returns the value of an ability based on the rules above.

julia> ability()
14

Note

This exercise is not about random distributions, therefore you don't have to simulate four dice rolls. You can use random values between 3 and 18 (inclusive) for the ability values, regardless of their distribution.

2. Calculate the constitution modifier

Implement a function modifier(ability) that returns an ability modifier based on the value of ability according to the rules above. The returned value must be an integer.

julia> modifier(17)
3

3. Write a random character generator that follows the rules above

Implement a DNDCharacter struct with three constructors:

Constructor	Description
`DNDCharacter()`	Create a character with randomly generated abilities.
`DNDCharacter(strength, dexterity, constitution, intelligence, wisdom, charisma, hitpoints)`	Create a character with given abilities using positional arguments.
`DNDCharacter(; strength, dexterity, constitution, intelligence, wisdom, charisma, hitpoints)`	Create a character with given abilities using keyword arguments.

julia> DNDCharacter()
DNDCharacter(18, 17, 18, 17, 5, 10, 14)

julia> DNDCharacter(4, 12, 13, 18, 13, 7, 11)
DNDCharacter(4, 12, 13, 18, 13, 7, 11)

julia> DNDCharacter(
           strength = 4,
           dexterity = 12,
           constitution = 13,
           intelligence = 18,
           wisdom = 13,
           charisma = 7,
           hitpoints = 11
       )
DNDCharacter(4, 12, 13, 18, 13, 7, 11)

julia