Functions and Methods

Key Distinction

Functions return a value (use RETURN statement).

Methods perform a task without returning a value.

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Function Example (Returns a Value)

Functions are used when a result is needed for further processing.

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

How to use functions

// The returned value is stored in a variable
int studentResult = CalculateFinalScore(35, 55);

// The result can be reused elsewhere
Console.WriteLine($"Result: {studentResult}");

if (studentResult >= 50)
{
    Console.WriteLine("Pass");
}

When to Use Functions

• A result is needed for further processing
• A calculation must be reused
• A value must be tested in a condition

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Method Example (No Return Value)

Methods are used to perform actions without returning a value.

public static void DisplayFinalScore(int score)
{
    Console.WriteLine($"Final score: {score}");
    // No return statement - this is a method
}

How to use methods

int result = 90;

// Method performs an action (displays output)
DisplayFinalScore(result);

// No value is returned

When to Use Methods

• Display output to the user
• Update data
• Carry out procedures that don't need to return a value

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Function vs Method Side-by-Side

// Function: returns a value
int result = CalculateFinalScore(40, 50);

// Method: performs an action
DisplayFinalScore(result);

Recognition Pattern

Functions are used for calculations.

Methods are used for procedures or actions.

This pairing appears frequently in high-scoring SAC solutions.

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Complete Example

using System;

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);
    }

    // Method: displays score
    public static void DisplayFinalScore(int score)
    {
        Console.WriteLine($"Final score: {score}");
    }

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

        // Use methods (actions)
        DisplayMessage("Student Result:");
        DisplayFinalScore(result);

        if (result >= 50)
        {
            DisplayMessage("Status: Pass");
        }
        else
        {
            DisplayMessage("Status: Fail");
        }
    }
}

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More Function Examples

Calculate average

public static float CalculateAverage(int[] scores)
{
    int total = 0;
    foreach (int score in scores)
    {
        total += score;
    }
    return (float)total / scores.Length;
}

Check if passing

public static bool IsPassing(int score)
{
    return score >= 50;
}

Calculate discount

public static float ApplyDiscount(float price, float discountRate)
{
    float discount = price * discountRate;
    float finalPrice = price - discount;
    return finalPrice;
}

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More Method Examples

Display welcome message

public static void DisplayWelcome(string username)
{
    Console.WriteLine($"Welcome, {username}!");
    Console.WriteLine("Please select an option from the menu.");
}

Save data

public static void SaveToFile(string data, string filename)
{
    File.WriteAllText(filename, data);
    Console.WriteLine("Data saved successfully.");
}

Clear screen and show header

public static void ShowHeader(string title)
{
    Console.Clear();
    Console.WriteLine("=".PadRight(50, '='));
    Console.WriteLine(title.PadLeft((50 + title.Length) / 2));
    Console.WriteLine("=".PadRight(50, '='));
}

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Quick Reference

Feature	Function	Method
Returns a value	✅ Yes	❌ No
Performs a task	✅ Yes	✅ Yes
Used in expressions	✅ Yes	❌ No
Has RETURN statement	✅ Yes	❌ No
Common use	Calculations	Procedures/Actions