Named arguments in C Sharp (C#) - Practice Problems & Coding Challenges

Challenge - 5 Problems

❓ Predict Output

intermediate

Output of method call with named arguments

What is the output of this C# code using named arguments?

C Sharp (C#)

using System;
class Program {
    static void PrintInfo(string name, int age, string city) {
        Console.WriteLine($"Name: {name}, Age: {age}, City: {city}");
    }
    static void Main() {
        PrintInfo(age: 30, city: "Paris", name: "Alice");
    }
}

A Name: age, Age: 30, City: Paris

B Name: Alice, Age: city, City: 30

C Name: , Age: 0, City:

D Name: Alice, Age: 30, City: Paris

💡 Hint

Named arguments allow you to specify parameters in any order by naming them explicitly.

The method PrintInfo is called with named arguments, so the order does not matter. The values are assigned correctly to name, age, and city.

❓ Predict Output

intermediate

Output with mixed positional and named arguments

What will this C# program print?

C Sharp (C#)

using System;
class Program {
    static void Display(string first, string second, string third) {
        Console.WriteLine($"{first} - {second} - {third}");
    }
    static void Main() {
        Display("One", third: "Three", second: "Two");
    }
}

A One - Two - Three

B One - Three - Two

C Three - Two - One

D Two - One - Three

💡 Hint

Positional arguments must come before named arguments.

The first argument is positional and assigned to 'first'. The named arguments assign 'second' and 'third' explicitly, so the output is 'One - Two - Three'.

🔧 Debug

advanced

Identify the error with named arguments

What error does this C# code produce?

C Sharp (C#)

class Program {
    static void Foo(int x, int y) {}
    static void Main() {
        Foo(y: 5, 10);
    }
}

A Runtime error: ArgumentException

B Compile-time error: positional argument follows named argument

C Compile-time error: missing argument for parameter 'x'

D No error, runs successfully

💡 Hint

In C#, positional arguments must come before named arguments.

The code tries to pass a positional argument after a named argument, which is not allowed and causes a compile-time error.

🧠 Conceptual

advanced

Effect of named arguments on method overload resolution

Given these method overloads, which call will compile without error?

C Sharp (C#)

class Program {
    static void Bar(int x, int y) {}
    static void Bar(int x, string y) {}
    static void Main() {
        // Which call is valid?
    }
}

A Bar(x: 5, y: 10);

B Bar(y: 10, x: 5);

C Bar(x: 5, y: "hello");

D Bar(y: "hello", x: 5);

💡 Hint

Named arguments do not change the types expected by the overloads.

Only Bar(x: 5, y: "hello") matches the overload with int and string parameters. The others cause ambiguity or type mismatch.

❓ Predict Output

expert

Output of method with optional and named arguments

What is the output of this C# program?

C Sharp (C#)

using System;
class Program {
    static void PrintDetails(string name, int age = 20, string city = "Unknown") {
        Console.WriteLine($"Name: {name}, Age: {age}, City: {city}");
    }
    static void Main() {
        PrintDetails(city: "Berlin", name: "Bob");
    }
}

A Name: Bob, Age: 20, City: Berlin

B Name: Bob, Age: 0, City: Berlin

C Name: Bob, Age: , City: Berlin

D Name: , Age: 20, City: Berlin

💡 Hint

Optional parameters use default values if not provided.

The call provides 'name' and 'city' by name. 'age' is omitted, so default 20 is used.