C# Syntax and Fundamentals

# CHAPTER 2

C# Syntax and Fundamentals #

1. Introduction #

2. Learning Objectives #

• End C# statements correctly with a semicolon ;.

• Declare and initialize Variables to store game data.

• Understand core Data Types: int, float, string, and bool.

• Perform mathematical operations (+, -, *, /).

• Use line and block comments to document your code.

3. The Semicolon (The Period of C#) #

Console.WriteLine("Hello"); // Correct
Console.WriteLine("World")  // ERROR! Missing semicolon

4. Variables and Data Types #

• int (Integer): Whole numbers. Used for ammo, level, or score.

• float: Decimal numbers. Used for speed, movement, or exact positioning. *Must end with an 'f'.*

• string: Text. Used for player names or dialogue.

• bool (Boolean): True or False. Used for states like isDead or hasKey.

// Syntax: DataType variableName = value;
int ammo = 30;
float walkSpeed = 5.5f;
string enemyName = "Goblin";
bool isPoisoned = false;

5. Math Operators #

• + (Add), - (Subtract), * (Multiply), / (Divide)

• Shorthand Operators: Gamers constantly modify variables. Instead of writing ammo = ammo - 1;, C# provides shortcuts:

• ammo -= 1; (Subtracts 1)

• ammo--; (Exactly the same, decrements by exactly 1)

• score += 100; (Adds 100 to the current score)

6. Comments (Leaving Notes) #

• Single-line comment: Use //

• Multi-line comment: Use /* to start and */ to end.

// This subtracts health from the player
health -= 20; 

/* 
  TODO: Add a particle explosion here later.
  Make sure the sound effect plays first.
*/

7. Visual Learning: Variable Memory Map #

[ COMPUTER MEMORY (RAM) ]
+-------------------+-------------------+-------------------+
| int playerLevel   | float jumpForce   | bool isJumping    |
| [ 5 ]             | [ 12.5f ]         | [ true ]          |
+-------------------+-------------------+-------------------+

8. Best Practices #

• Camel Case Naming: Always name your variables using camelCase. The first word is lowercase, and every subsequent word is Capitalized. Do not use spaces.

• Good: maxHealth, playerMovementSpeed

• Bad: Maxhealth, player movement speed, pms

9. Common Mistakes #

• Forgetting the 'f' on Floats: If you type float speed = 5.5;, C# will throw an error. By default, C# assumes all decimals are double (a massive data type). You must explicitly append an 'f' (5.5f) to tell C# it is a lightweight float, which is the standard for game engines like Unity.

10. Mini Project: The Player Profile #

1. 1. Open your Visual Studio Console project.

1. 2. In the Main function, write the following:

using System;

class Program
{
    static void Main()
    {
        // 1. Declare Variables
        string heroName = "Arthur";
        int level = 5;
        float gold = 150.5f;
        bool hasSword = true;

        // 2. Perform Math
        level++; // Arthur leveled up!
        gold += 50.0f; // Arthur found gold!

        // 3. Output to Console (Concatenation)
        Console.WriteLine("Hero: " + heroName);
        Console.WriteLine("Level: " + level);
        Console.WriteLine("Gold: " + gold);
        Console.WriteLine("Equipped Sword: " + hasSword);
    }
}

1. 3. Press Play. Watch the math process and output the updated player profile!

11. Practice Exercises #

1. 1. Write a line of code to declare a whole-number variable representing the number of lives a player has, and set it to 3.

1. 2. What is the shorthand code to increase an integer variable named score by exactly 10 points?

12. MCQs with Answers #

13. Interview Questions #

• Q: Explain the difference between an int, a float, and a double in C#. Why do game engines primarily use float for 3D coordinates instead of double?

• Q: What is variable initialization, and what happens if you try to use a variable in C# that has been declared but not initialized?

• Q: Walk me through the concept of "Strongly Typed" languages versus "Dynamically Typed" languages. Why is C# considered strongly typed?

14. FAQs #

15. Summary #

16. Next Chapter Recommendation #