C# Tutorial 6.2: Parameters and return types

 In C#, a method is a block of code that performs a specific task, and parameters and return types are crucial components of method signatures.

Parameters:

1. Defining a Method with Parameters:

In C#, you can define a method with parameters to receive input values.

class Program
{
    // Method with parameters
    static void PrintMessage(string message)
    {
        Console.WriteLine(message);
    }
    static void Main()
    {
        // Calling the method with an argument
        PrintMessage("Hello, C#!");
    }
}

In this example, PrintMessage is a method that takes a string parameter named message.

2. Multiple Parameters:

You can have multiple parameters in a method.

class Program
{
    // Method with multiple parameters
    static void PrintDetails(string name, int age)
    {
        Console.WriteLine($"Name: {name}, Age: {age}");
    }
    static void Main()
    {
        // Calling the method with multiple arguments
        PrintDetails("John Doe", 25);
    }
}

3. Default Values:

You can provide default values for parameters.

class Program
{
    // Method with a default parameter value
    static void PrintGreeting(string name, string greeting = "Hello")
    {
        Console.WriteLine($"{greeting}, {name}!");
    }
    static void Main()
    {
        // Calling the method with and without providing the second argument
        PrintGreeting("Alice");
        PrintGreeting("Bob", "Hi");
    }
}

Return Types:

1. Methods with Return Types:

A method can return a value. Specify the return type in the method signature.

class Program
{
    // Method with a return type
    static int Add(int a, int b)
    {
        return a + b;
    }
    static void Main()
    {
        // Calling the method and storing the result
        int sum = Add(3, 5);
        Console.WriteLine($"Sum: {sum}");
    } 
}

2. Void Return Type:

If a method doesn't return any value, use the void return type.

class Program
{
    // Method with void return type
    static void DisplayMessage(string message)
    {
        Console.WriteLine(message);
    }
    static void Main()
    {
        // Calling the method with no need to store the result
        DisplayMessage("Welcome to C#!");
    } 
}

3. Returning Objects:

A method can also return objects of custom classes or built-in types.

class Program
{
    // Method returning an object
    static Person CreatePerson(string name, int age)
    {
        return new Person { Name = name, Age = age };
    }
    static void Main()
    {
        // Calling the method and working with the returned object
        Person person = CreatePerson("Jane Doe", 30);
        Console.WriteLine($"Person: {person.Name}, Age: {person.Age}");
    }
}
// Custom class for demonstration
class Person
{
    public string Name { get; set; }
    public int Age { get; set; }
}

Now you have a basic understanding of how to work with parameters and return types in C#. Feel free to experiment and build upon these concepts in your own projects!