Try It Yourself - SyntaxStudy Editor

HTML / CSS / JS

// Optional parameters, named arguments, and params

static string BuildEmail(
    string to,
    string subject,
    string body           = "",
    bool   isHtml         = false,
    string from           = "no-reply@example.com",
    int    priority       = 3)
{
    string type = isHtml ? "HTML" : "Plain";
    return $"From:{from} To:{to} Subject:{subject} Type:{type} Priority:{priority}";
}

// All positional
Console.WriteLine(BuildEmail("alice@example.com", "Hi"));

// Named arguments — skip optional ones in the middle
Console.WriteLine(BuildEmail(
    to:       "bob@example.com",
    subject:  "Report",
    isHtml:   true,
    priority: 1));

// params — variable argument count
static int Sum(params int[] numbers)
{
    int total = 0;
    foreach (int n in numbers) total += n;
    return total;
}

Console.WriteLine(Sum(1, 2, 3));           // 6
Console.WriteLine(Sum(10, 20));            // 30
Console.WriteLine(Sum());                  // 0

// Combining required, optional, and params
static void Log(string level = "INFO", params string[] messages)
{
    foreach (string msg in messages)
        Console.WriteLine($"[{level}] {msg}");
}

Log("WARN", "Disk full", "Check storage");
Log(messages: new[] { "Server started" });  // named params array