07. Methods in C#

Level: Beginner

ℹ️ What You'll Learn

What a method is
Why methods are useful
Create a method with no return value
Create a method with parameters
Create a method that returns a value
Reuse methods for marks, grades, and reports
Avoid common method mistakes

In the previous articles, you wrote code directly in Program.cs.

When code grows, writing everything in one place becomes messy.

Methods help us organize code into small reusable blocks.

The Problem: Repeating the Same Code

Imagine you need to print student details for many students.

Without methods:

Console.WriteLine("Name: Sahasra");
Console.WriteLine("Class: 10-A");
Console.WriteLine("Result: Pass");

Console.WriteLine("Name: Priya");
Console.WriteLine("Class: 10-A");
Console.WriteLine("Result: Pass");

This repeats the same pattern.

With a method:

PrintStudent("Sahasra", "10-A", "Pass");
PrintStudent("Priya", "10-A", "Pass");

Cleaner and reusable.

What is a Method?

A method is a named block of code that performs one job.

static void SayHello()
{
    Console.WriteLine("Hello C#");
}

To run the method, call it:

SayHello();

Method Syntax

static returnType MethodName(parameters)
{
    // code
}

Part	Meaning
`static`	Used for beginner console examples
`returnType`	What the method gives back
`MethodName`	Name of the method
`parameters`	Inputs to the method
`{ }`	Method body

Quick Definitions

Method - Named block of reusable code
Parameter - Input to a method (defined in method signature)
Argument - Value passed to method when called
Return value - Output that method gives back
Return type - Data type of the return value
Void - Method returns nothing
Static - Method belongs to the program itself (not an object)
Scope - Where a variable can be used
Composition - Multiple methods working together

Understanding the `static` Keyword

For beginners: static means the method belongs to the program itself, not to an individual object.

In beginner console apps:

All methods are static
All methods belong to "Program"
You call them directly by name

static void SayHello()
{
    Console.WriteLine("Hello");
}

SayHello();  // Call directly (because it's static)

Don't worry: You'll understand static deeply in Article 08 (Classes & Objects) when you create instances of classes. For now: all methods are static in console apps.

How Methods Work: Visual Flow

When you call a method:

Main Program
    |
    v
PrintWelcome();  <- Method call
    |
    v
Enter method -> PrintWelcome
    |
    v
Execute code -> Console.WriteLine("Welcome to SMS")
    |
    v
Return to caller
    |
    v
Continue in Main Program

Key: When method runs, main program WAITS. When method finishes (return), main program continues.

Step 1: void Method

void means the method does not return a value.

Example:

static void PrintWelcome()
{
    Console.WriteLine("Welcome to School Management System");
}

PrintWelcome();

Use void when the method only performs an action, like printing.

Step 2: Method with Parameters

Parameters are input values.

static void PrintStudent(string name, string className, string result)
{
    Console.WriteLine("=== Student Details ===");
    Console.WriteLine($"Name: {name}");
    Console.WriteLine($"Class: {className}");
    Console.WriteLine($"Result: {result}");
}

PrintStudent("Sahasra Kumar", "10-A", "Pass");
PrintStudent("Priya Sharma", "10-A", "Pass");

Here:

Parameter	Example value
`name`	`"Sahasra Kumar"`
`className`	`"10-A"`
`result`	`"Pass"`

Parameters vs Arguments

Parameters are written in the method definition.

Arguments are actual values passed during the method call.

static void PrintName(string name)
{
    Console.WriteLine(name);
}

PrintName("Sahasra");

Word	Example
Parameter	`string name`
Argument	`"Sahasra"`

Step 3: Method with Return Value

Some methods calculate and return a result.

Example: calculate total marks.

static int CalculateTotal(int english, int maths, int science)
{
    int total = english + maths + science;
    return total;
}

int totalMarks = CalculateTotal(80, 90, 70);
Console.WriteLine($"Total: {totalMarks}");

return sends the value back to the caller.

Step 4: Calculate Percentage Method

static double CalculatePercentage(int totalMarks, int maxMarks)
{
    double percentage = (double)totalMarks / maxMarks * 100;
    return percentage;
}

int total = 424;
double percentage = CalculatePercentage(total, 500);

Console.WriteLine($"Percentage: {percentage:F2}");

Step 5: Get Result Method

static string GetResult(double percentage)
{
    if (percentage >= 35)
    {
        return "Pass";
    }

    return "Fail";
}

string result = GetResult(84.8);
Console.WriteLine(result);

Important:

When return runs, method stops immediately.

Step 6: Get Grade Method

static string GetGrade(double percentage)
{
    if (percentage >= 90)
    {
        return "A+";
    }
    else if (percentage >= 80)
    {
        return "A";
    }
    else if (percentage >= 70)
    {
        return "B";
    }
    else if (percentage >= 60)
    {
        return "C";
    }
    else if (percentage >= 35)
    {
        return "D";
    }

    return "F";
}

Call it:

string grade = GetGrade(84.8);
Console.WriteLine($"Grade: {grade}");

Step 7: Method with Array Parameter

Methods can receive arrays also.

static int CalculateTotal(int[] marks)
{
    int total = 0;

    foreach (int mark in marks)
    {
        total += mark;
    }

    return total;
}

int[] studentMarks = { 82, 91, 78, 85, 88 };
int total = CalculateTotal(studentMarks);

Console.WriteLine($"Total: {total}");

Full Example: Report Card Using Methods

💻 Try It — Console App

💡 Paste into Program.cs and press F5⌥ GitHub

static int CalculateTotal(int[] marks)
{
    int total = 0;

    foreach (int mark in marks)
    {
        total += mark;
    }

    return total;
}

static double CalculatePercentage(int totalMarks, int maxMarks)
{
    return (double)totalMarks / maxMarks * 100;
}

static string GetResult(double percentage)
{
    if (percentage >= 35)
    {
        return "Pass";
    }

    return "Fail";
}

static string GetGrade(double percentage)
{
    if (percentage >= 90)
    {
        return "A+";
    }
    else if (percentage >= 80)
    {
        return "A";
    }
    else if (percentage >= 70)
    {
        return "B";
    }
    else if (percentage >= 60)
    {
        return "C";
    }
    else if (percentage >= 35)
    {
        return "D";
    }

    return "F";
}

static void PrintReportCard(string name, string className, int[] marks)
{
    int total = CalculateTotal(marks);
    int maxMarks = marks.Length * 100;
    double percentage = CalculatePercentage(total, maxMarks);
    string result = GetResult(percentage);
    string grade = GetGrade(percentage);

    Console.WriteLine("=== Report Card ===");
    Console.WriteLine($"Name: {name}");
    Console.WriteLine($"Class: {className}");
    Console.WriteLine($"Total: {total}/{maxMarks}");
    Console.WriteLine($"Percentage: {percentage:F2}");
    Console.WriteLine($"Grade: {grade}");
    Console.WriteLine($"Result: {result}");
}

int[] raviMarks = { 82, 91, 78, 85, 88 };
PrintReportCard("Sahasra Kumar", "10-A", raviMarks);

Expected output:

=== Report Card ===
Name: Sahasra Kumar
Class: 10-A
Total: 424/500
Percentage: 84.80
Grade: A
Result: Pass

Method Naming Rules

Use meaningful action names.

Good Name	Meaning
`CalculateTotal`	Calculates a total
`CalculatePercentage`	Calculates percentage
`GetGrade`	Returns grade
`GetResult`	Returns pass/fail
`PrintReportCard`	Prints report card
`IsEligibleForExam`	Returns true/false

Avoid names like:

static int DoIt()
static string Get()
static void Method1()

Small Note: Default Parameters

Default parameters give a value when the caller does not pass one.

static void EnrollStudent(string name, string className, string section = "A")
{
    Console.WriteLine($"{name} enrolled in {className}-{section}");
}

EnrollStudent("Sahasra", "10");
EnrollStudent("Priya", "10", "B");

Output:

Sahasra enrolled in 10-A
Priya enrolled in 10-B

Use default parameters only when the default value is obvious.

Small Note: Method Overloading

Method overloading means same method name with different parameters.

static void PrintStudent(string name)
{
    Console.WriteLine(name);
}

static void PrintStudent(string name, string className)
{
    Console.WriteLine($"{name} - {className}");
}

PrintStudent("Sahasra");
PrintStudent("Sahasra", "10-A");

Learn the basic method concept first. Overloading becomes more useful later.

Quick Reference

Need	Method Type
Print something	`void` method
Calculate and send value back	return method
Send input to method	parameters
Reuse repeated code	method
Return true/false	`bool` method

When You'll Use This in SMS

Methods organize SMS features.

Grade calculation:

GetGrade(84.8) -> "A"

Fee calculation:

CalculateBalance(30000, 15000) -> 15000

Report generation:

PrintReportCard("Sahasra", marks) -> Full report printed

Eligibility check:

IsEligible(hasPaid, hasAttended) -> true/false

Real impact:

Methods organize code into features
Same method used for all students = consistency
Change method once = affects entire SMS
Production SMS has thousands of methods, all working together

Try This Now

Run the report card example above. Then experiment:

Change student name to your name
Change marks: int[] yourMarks = { 90, 85, 88 };
Run and see your own report card
Create new method: CalculateAttendancePercentage()

See how methods make code reusable for any student.

ℹ️ Video Tutorial

Methods explained: creating, calling, parameters, return values. Video coming soon. Subscribe to NexCoding YouTube for updates.

Common Mistakes

Mistake 1: Method says it returns value but does not return

Wrong:

static string GetResult(double percentage)
{
    if (percentage >= 35)
    {
        Console.WriteLine("Pass");
    }
}

Correct:

static string GetResult(double percentage)
{
    if (percentage >= 35)
    {
        return "Pass";
    }

    return "Fail";
}

Mistake 2: Wrong return type

Wrong:

static int GetResult()
{
    return "Pass";
}

Correct:

static string GetResult()
{
    return "Pass";
}

Mistake 3: Forgetting to call the method

Wrong:

static void PrintWelcome()
{
    Console.WriteLine("Welcome");
}

This only defines the method. It does not run.

Correct:

PrintWelcome();

Mistake 4: Doing too many things in one method

Avoid one huge method that calculates, prints, reads input, saves data, and validates everything.

Better:

CalculateTotal
CalculatePercentage
GetGrade
PrintReportCard

Best Practices

One method should do one clear job.
Use meaningful method names.
Use parameters instead of duplicate code.
Return values when caller needs the result.
Use void only when no result is needed.
Keep methods small and readable.
Test one method at a time.
Avoid advanced method features until basics are clear.

Practice Task

Create these methods:

CalculateBalance(totalFees, paidAmount)
GetFeeStatus(balance)
PrintFeeReport(studentName, totalFees, paidAmount)

Rules:

Balance = total fees - paid amount
If balance is 0, status is Paid
If balance is greater than 0, status is Pending

Starter:

static decimal CalculateBalance(decimal totalFees, decimal paidAmount)
{
    return totalFees - paidAmount;
}

static string GetFeeStatus(decimal balance)
{
    if (balance == 0)
    {
        return "Paid";
    }

    return "Pending";
}

static void PrintFeeReport(string studentName, decimal totalFees, decimal paidAmount)
{
    decimal balance = CalculateBalance(totalFees, paidAmount);
    string status = GetFeeStatus(balance);

    Console.WriteLine("=== Fee Report ===");
    Console.WriteLine($"Student: {studentName}");
    Console.WriteLine($"Total Fees: {totalFees}");
    Console.WriteLine($"Paid Amount: {paidAmount}");
    Console.WriteLine($"Balance: {balance}");
    Console.WriteLine($"Status: {status}");
}

PrintFeeReport("Priya Sharma", 40000.00m, 25000.00m);

Quick Revision

Question	Answer
What is a method?	A reusable block of code
What does `void` mean?	Method returns nothing
What are parameters?	Inputs to a method
What does `return` do?	Sends value back and stops method
Why use methods?	Reuse code and organize logic
What should method names be?	Clear action names

🎯 Q1: What is a method in C#?

A method is a reusable block of code that performs one job.

Example:

static void PrintWelcome()
{
    Console.WriteLine("Welcome");
}

Call it:

PrintWelcome();

🎯 Q2: What is the difference between void and return type?

void means the method does not return a value.

A return type like int, string, or bool means the method gives a value back.

Example:

static void PrintName(string name)
{
    Console.WriteLine(name);
}

static string GetResult(double percentage)
{
    return percentage >= 35 ? "Pass" : "Fail";
}

🎯 Q3: What are parameters and arguments?

Parameters are inputs in the method definition.

Arguments are actual values passed during the call.

static void PrintStudent(string name)
{
    Console.WriteLine(name);
}

PrintStudent("Sahasra");

string name is a parameter.

"Sahasra" is an argument.

🎯 Q4: Why do we use methods?

We use methods to:

Avoid duplicate code
Organize logic
Reuse code
Make code easier to test
Make programs easier to read

🎯 Q5: What happens when return runs?

When return runs, the method stops immediately and sends a value back.

Example:

static string GetResult(double percentage)
{
    if (percentage >= 35)
    {
        return "Pass";
    }

    return "Fail";
}

🎯 Q6: What is method overloading?

Method overloading means using the same method name with different parameters.

Example:

static void PrintStudent(string name)
{
    Console.WriteLine(name);
}

static void PrintStudent(string name, string className)
{
    Console.WriteLine($"{name} - {className}");
}

The compiler chooses the correct method based on arguments.

🤖Use AI to Learn Faster

⚠️ Important for beginners: Do NOT use AI to write your code yet. Type every example yourself. Your brain learns by doing, not by reading AI output. Use AI only to explain and quiz you — not to code for you. Once you have strong fundamentals, AI becomes a powerful productivity tool for repetitive tasks.

Use ChatGPT, Claude, or Copilot to go deeper on C# methods. Try these prompts:

"Explain C# methods using school report card examples"
"Give me 10 beginner practice questions for methods"
"Explain void, parameters, arguments, and return values simply"
"Quiz me with 5 beginner questions about C# methods"

💡 Tip: After reading this article, paste your own code into AI and ask "What could go wrong here and why?" — fastest way to find edge cases and deepen understanding.

OOP Part 1 - Classes and Objects ->

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The Problem: Repeating the Same Code​

What is a Method?​

Method Syntax​

Quick Definitions​

Understanding the static Keyword​

How Methods Work: Visual Flow​

Step 1: void Method​

Step 2: Method with Parameters​

Parameters vs Arguments​

Step 3: Method with Return Value​

Step 4: Calculate Percentage Method​

Step 5: Get Result Method​

Step 6: Get Grade Method​

Step 7: Method with Array Parameter​

Full Example: Report Card Using Methods​

Method Naming Rules​

Small Note: Default Parameters​

Small Note: Method Overloading​

Quick Reference​

When You'll Use This in SMS​

Try This Now​

Common Mistakes​

Best Practices​

Practice Task​

Quick Revision​

Next Article​

The Problem: Repeating the Same Code

What is a Method?

Method Syntax

Quick Definitions

Understanding the `static` Keyword

How Methods Work: Visual Flow

Step 1: void Method

Step 2: Method with Parameters

Parameters vs Arguments

Step 3: Method with Return Value

Step 4: Calculate Percentage Method

Step 5: Get Result Method

Step 6: Get Grade Method

Step 7: Method with Array Parameter

Full Example: Report Card Using Methods

Method Naming Rules

Small Note: Default Parameters

Small Note: Method Overloading

Quick Reference

When You'll Use This in SMS

Try This Now

Common Mistakes

Best Practices

Practice Task

Quick Revision

Next Article