e. Extras

This page provides drop-in C# templates (like we did for file I/O) and shows exactly how they are used inside a program.

Programming Support (Non-examinable)

Exams assess the concepts (scope, return values, class vs object), not syntax.

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1) Constants + scope (the "one place to change it" pattern)

public static class AppConfig
{
    // Constant: fixed value that must not change
    public const int MAX_ATTEMPTS = 3;

    // Constant: fixed rate (example)
    public const decimal TAX_RATE = 0.10m;
}

How it's used

if (attempts >= AppConfig.MAX_ATTEMPTS)
{
    Console.WriteLine("No attempts remaining.");
}

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2) Global vs local variables (safe pattern)

Global variable example (program-wide state)

public static class AppState
{
    // Global variable: used across multiple modules
    public static int TotalStudents = 0;
}

Local variable example (inside a method)

public static void AddStudent(string name)
{
    int nameLength = name.Length; // local variable
    AppState.TotalStudents++;     // global variable updated
}

Teacher note

Use globals sparingly — locals reduce unintended changes.

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3) Function vs method templates (C#)

Function (returns a value)

public static int CalculateFinalScore(int testScore, int examScore)
{
    int finalScore = testScore + examScore; // local variable
    return finalScore;                      // RETURN value => function (VCAA concept)
}

How it's used

int result = CalculateFinalScore(35, 55);

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Method (does not return a value)

public static void DisplayFinalScore(int score)
{
    Console.WriteLine($"Final score: {score}"); // action only, no return value
}

How it's used

DisplayFinalScore(result);

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✅ Correct order students should copy

int result = CalculateFinalScore(35, 55); // function
DisplayFinalScore(result);                // method

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4) Class + object templates (drop-in)

Class (blueprint)

public class Student
{
    // Attributes (data)
    public string Name { get; set; } = "";
    public int Score { get; set; }

    public Student(string name, int score)
    {
        Name = name;
        Score = score;
    }

    // Behaviour (method)
    public void PrintDetails()
    {
        Console.WriteLine($"{Name}: {Score}");
    }
}

Object (instance) + usage

Student student1 = new Student("Alex", 85);

student1.PrintDetails();

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5) FULL mini-program example (shows everything working together)

This demonstrates:

• constants
• global + local variables
• function + method usage
• class + object creation

using System;

public static class AppConfig
{
    public const int MAX_SCORE = 100;
    public const decimal TAX_RATE = 0.10m;
}

public static class AppState
{
    public static int TotalStudents = 0; // global variable
}

public class Student
{
    public string Name { get; set; } = "";
    public int Score { get; set; }

    public Student(string name, int score)
    {
        Name = name;
        Score = score;
    }

    public void PrintDetails()
    {
        Console.WriteLine($"{Name}: {Score}");
    }
}

public class Program
{
    // Function: returns a value
    public static int CalculateFinalScore(int testScore, int examScore)
    {
        int finalScore = testScore + examScore;  // local variable
        return finalScore;
    }

    // Method: performs an action (no return)
    public static void DisplayMessage(string msg)
    {
        Console.WriteLine(msg);
    }

    public static void Main()
    {
        // Use a function (returns a value)
        int rawScore = CalculateFinalScore(45, 60);
        int finalScore;

        // Use a constant to enforce a rule
        if (rawScore > AppConfig.MAX_SCORE)
        {
            finalScore = AppConfig.MAX_SCORE;
        }
        else
        {
            finalScore = rawScore;
        }

        // Create an object from a class using the constructor
        Student s = new Student("Jordan", finalScore);

        // Update a global variable
        AppState.TotalStudents++;

        // Use methods (actions)
        DisplayMessage("Student saved:");
        s.PrintDetails();
        DisplayMessage($"Total students recorded: {AppState.TotalStudents}");
    }
}

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40+ Exam phrasing (students should memorise)

Essential exam phrases

✅ "A local variable is only accessible within the function/method where it is declared."

✅ "A global variable can be accessed throughout the program, which can increase risk of unintended modification."

✅ "A constant is used for fixed values to improve reliability and maintainability."

✅ "A function returns a value using a RETURN statement."

✅ "A method performs a task and does not return a value."

✅ "A class is a blueprint; an object is an instance created from the class."