Lab: Fields

Objective

In this lab, we will transform procedural C# code into slightly more object oriented code by introducing classes with fields. We have a long way to go before we can call this code object oriented but we’ve got to start somewhere. By using fields we group related data in separate classes.

Provided Code

Carefully review the provided code. Notice the use of separate variables to represent the attributes of a player and an enemy. This dispersed method of managing data illustrates a lack of encapsulation that we will address.

// Player attributes
int playerHealth = 100;
int playerArmor = 50;
int playerDamage = 30;
string playerName = "Hero";

// Enemy attributes
int enemyHealth = 150;
int enemyArmor = 20;
int enemyDamage = 20;
string enemyName = "Orc";

The below script needs to be able to find the current output cell; this is an easy method to get it.

Here, we have loosely related variables that could represent a player’s and an enemy’s characteristics in a simple game scenario. Our task is to group these variables into classes, converting this procedural style into an object oriented approach.

Instructions

We will begin the process of organizing this data by creating two classes: Player and Enemy. Each class will be equipped with public fields that are pertinent to the entity it represents.

Step 1: Define the Player Class

Create a Player class containing public fields for health, armor, and name.

class Player
{
    public string Name;
    public int Health;
    public int Armor;
    public int Damage;
}

Step 2: Define the Enemy Class

In a similar fashion, define an Enemy class with public fields for health, damage, and name.

class Enemy
{
    public string Name;
    public int Health;
    public int Armor;
    public int Damage;
}

Step 3: Unify the Classes

Wait a minute, at this point we realize that both classes contain exactly the same data. We don’t need separate classes, we need separate instances of the same class.

Remove the two classes and replace them with a new class called Character.

class Character
{
    public string Name;
    public int Health;
    public int Armor;
    public int Damage;
}

Step 4: Replace Global Variables with Instances

Replace the global variables in the Main method with instances of the Player and Enemy classes, assigning the values appropriately to the public fields.

Character player = new Character();
player.Name = "Hero";
player.Health = 100;
player.Armor = 50;
player.Damage = 30;

Character enemy = new Character();
enemy.Health = 150;
enemy.Armor = 20;
enemy.Damage = 20;
enemy.Name = "Orc";

🤔 Reflection

Think about the impact of organizing variables into classes with fields. Does it make your code more analyzable?

Step 5: Print Character Status

Add a local function or static method to the Main method or Program class with the signature void Print(Character character) that prints all the data related to a character.

static void print (Character character)
{
    Console.WriteLine($"{character.Name}: ❤️ {character.Health}  🛡️ {character.Armor}  ⚔️ {character.Damage}");
}

// If you want to use a local function:
void Print(Character character)
{
    Console.WriteLine($"{character.Name}: ❤️ {character.Health}  🛡️ {character.Armor}  ⚔️ {character.Damage}");
}

Print(player);
Print(enemy);

Hero: ❤️ 100  🛡️ 50  ⚔️ 30

Orc: ❤️ 150  🛡️ 20  ⚔️ 20

Challenge

Write a local function or static method with the signature void Attack (Character attacker, Character attacked). The method should apply the Damage of the attacker object to the Armor of the attacked object. The Armor should never be negative, and if the Damage exceeds the Armor then the remaining Damage should be applied to Health. The method should also print information about who’s attacking who. It should behave something like this:

Print(enemy);
Attack(player, enemy);
Print(enemy);

Orc: ❤️ 150  🛡️ 20  ⚔️ 20

Hero attacks Orc

Orc: ❤️ 140  🛡️ 0  ⚔️ 20

Conclusion

As we learn more about object oriented programming we will realize that the Print and Attack methods should not be local functions or static methods but instance methods. But let’s take it one step at a time.

Good job! 🥳