Unity & C# Cheat Sheet

📦 Variables & Types

public int health = 100;
public string playerName = "Pip";
public float speed = 4.5f;
private bool isAlive = true;
const int MAX_HP = 100;
[SerializeField] private float jumpForce = 12f;

Use [SerializeField] to expose a private field in the Inspector. public fields show automatically.

⚙️ MonoBehaviour Lifecycle

void Awake() {
    // runs once, before Start
}

void Start() {
    // runs once, before first frame
}

void Update() {
    // runs every frame
    transform.Translate(Vector3.right * speed * Time.deltaTime);
}

void FixedUpdate() {
    // runs on a fixed physics timestep
}

🔁 Loops & Conditionals

if (health <= 0) {
    Destroy(gameObject);
} else if (health < 20) {
    Debug.Log("Low HP!");
} else {
    Debug.Log("OK");
}

foreach (GameObject enemy in enemies) {
    Destroy(enemy);
}

for (int i = 0; i < 10; i++) { }
while (ammo > 0) { ammo--; }

📡 Events & Delegates

public static event Action<int> OnHealthChanged;

void TakeDamage(int amount) {
    health -= amount;
    OnHealthChanged?.Invoke(health);
}

// subscribe elsewhere:
void OnEnable() {
    Player.OnHealthChanged += UpdateHpLabel;
}
void OnDisable() {
    Player.OnHealthChanged -= UpdateHpLabel;
}

C# events decouple systems one script broadcasts, others react without direct references.

🎮 Input & Movement

void Update() {
    float h = Input.GetAxis("Horizontal");
    float v = Input.GetAxis("Vertical");
    Vector3 dir = new Vector3(h, 0, v).normalized;
    rb.MovePosition(transform.position + dir * speed * Time.deltaTime);

    if (Input.GetButtonDown("Jump") && isGrounded) {
        rb.AddForce(Vector3.up * jumpForce, ForceMode.Impulse);
    }
}

🌳 GameObject & Transform Basics

🧱 Common Components

⏱️ Coroutines & Timing

• StartCoroutine(MyRoutine()) — begin a coroutine
• yield return new WaitForSeconds(1f); — wait one second
• yield return null; — wait one frame
• Time.deltaTime — seconds since last frame
• Time.timeScale = 0; — pause the game
• InvokeRepeating("Tick", 1f, 1f) — call a method repeatedly