Conditions and Loops

# CHAPTER 3

Conditions and Loops #

1. Introduction #

2. Learning Objectives #

• Use Comparison Operators (==, >, <) to evaluate data.

• Write if, else if, and else statements to branch game logic.

• Use switch statements to cleanly manage player states.

• Automate repetitive tasks using for and while loops.

• Understand how loops relate to spawning and inventory systems.

3. Comparison and Logical Operators #

• == (Is Equal To) *Note: A single = assigns a value; double == compares!*

• != (Is Not Equal To)

• >, <, >=, <= (Greater than, Less than, etc.)

• && (AND): Both conditions must be true.

• || (OR): Only one condition must be true.

4. If / Else Statements (The Crossroads) #

int health = 0;

if (health <= 0)
{
    Console.WriteLine("Player Died!"); // This will run
}
else if (health < 20)
{
    Console.WriteLine("Low Health Warning!");
}
else
{
    Console.WriteLine("Player is healthy.");
}

5. Switch Statements (The State Manager) #

string enemyState = "Patrol";

switch (enemyState)
{
    case "Patrol":
        Console.WriteLine("Walking back and forth.");
        break; // You MUST include 'break' to exit the switch!
    case "Chase":
        Console.WriteLine("Running at player!");
        break;
    default:
        Console.WriteLine("Standing idle.");
        break;
}

6. Loops (Repetitive Power) #

• The while loop: Runs continuously *as long as* a condition is true. Be careful—if the condition never becomes false, you create an "Infinite Loop" and crash the game!

• The for loop: The safest and most common loop. You tell it exactly how many times to run. It has three parts: (Start ; Condition ; Increment).

// Example: Spawning 5 enemies
// i starts at 0. As long as i < 5, run the code, then add 1 to i (i++).
for (int i = 0; i < 5; i++)
{
    Console.WriteLine("Spawned Enemy number: " + i);
}

7. Visual Learning: Logic Flowchart #

                   [ Start Check ]
                          |
             (Is Player Health <= 0?)
              /                      \
         [ YES ]                    [ NO ]
            |                          |
    Play Death Animation        Keep Playing Game
            |
        Show Menu

8. Best Practices #

• Curly Bracket Formatting: In C#, standard convention dictates that the opening curly bracket { goes on a *new line* beneath the if or for statement, unlike Java or JavaScript where it stays on the same line. Following this convention makes your C# code look professional to studio leads.

9. Common Mistakes #

• The Assignment vs. Comparison Typo:

10. Mini Project: The Damage Calculator #

1. 1. Open Visual Studio. Create a new Console App.

1. 2. Write the following combat logic:

using System;

class Program
{
    static void Main()
    {
        int playerArmor = 10;
        int enemyDamage = 25;
        bool isDefending = true;

        Console.WriteLine("An enemy attacks for 25 damage!");

        // If defending, armor is doubled!
        if (isDefending == true)
        {
            playerArmor *= 2; // playerArmor becomes 20
            Console.WriteLine("Player raises shield! Armor doubled to " + playerArmor);
        }

        // Calculate final damage (ensure it doesn't go below 0)
        int finalDamage = enemyDamage - playerArmor;
        if (finalDamage < 0)
        {
            finalDamage = 0;
        }

        Console.WriteLine("Player takes " + finalDamage + " final damage.");
    }
}

1. 3. Run the program. Change isDefending to false and run it again to see the branching logic at work!

11. Practice Exercises #

1. 1. Write a for loop that counts down from 10 to 1, printing each number to the console (like a bomb timer).

1. 2. What is the difference between the && operator and the || operator?

12. MCQs with Answers #

13. Interview Questions #

• Q: Explain the syntax structure of a for loop in C#. In what game development scenario would you explicitly choose a for loop over a while loop?

• Q: A junior programmer creates a while (isAlive) loop to handle the player's breathing animation, but the game immediately freezes and crashes. What is an Infinite Loop, and why did this happen?

• Q: How do switch statements improve code readability and performance compared to deeply nested if / else if chains when implementing an NPC State Machine?

14. FAQs #

15. Summary #

16. Next Chapter Recommendation #