Namespaces and using directives in C Sharp (C#) - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to include the System namespace.

C Sharp (C#)

using [1];

class Program {
    static void Main() {
        System.Console.WriteLine("Hello World");
    }
}

Drag options to blanks, or click blank then click option'

ASystem

BConsole

CCollections

DText

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'Console' instead of 'System' in the using directive.

Forgetting the semicolon after the using statement.

The 'using System;' directive allows access to the System namespace, which contains Console.

2fill in blank

medium

Complete the code to declare a namespace named MyApp.

C Sharp (C#)

namespace [1] {
    class Program {
        static void Main() {
            System.Console.WriteLine("Inside MyApp namespace");
        }
    }
}

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AMyApp

BApplication

CSystem

DConsole

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'System' instead of 'MyApp' as the namespace name.

Omitting the namespace keyword.

The namespace declaration uses the keyword 'namespace' followed by the desired name, here 'MyApp'.

3fill in blank

hard

Fix the error by completing the using directive to access List<T>.

C Sharp (C#)

using [1];

class Program {
    static void Main() {
        var list = new List<int>();
        list.Add(1);
        System.Console.WriteLine(list[0]);
    }
}

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ASystem.Linq

BSystem.Text

CSystem.IO

DSystem.Collections.Generic

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'System.Text' or 'System.IO' which do not contain List.

Forgetting to add the using directive for the generic collections.

List is in the System.Collections.Generic namespace, so you must include it with a using directive.

4fill in blank

hard

Fill both blanks to create a namespace and use a directive for Console.

C Sharp (C#)

[1] MyNamespace {
    [2] System;

    class Program {
        static void Main() {
            Console.WriteLine("Hello from MyNamespace");
        }
    }
}

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Anamespace

Busing

Cclass

Dpublic

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'class' instead of 'namespace' for the first blank.

Omitting the using directive for System.

The keyword 'namespace' declares a namespace, and 'using System;' allows access to Console without prefix.

5fill in blank

hard

Fill all three blanks to declare a namespace, include System, and define a class.

C Sharp (C#)

[1] MyApp {
    [2] System;

    [3] Program {
        static void Main() {
            Console.WriteLine("Welcome to MyApp");
        }
    }
}

Drag options to blanks, or click blank then click option'

Anamespace

Busing

Cclass

Dinterface

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'interface' instead of 'class' for the third blank.

Forgetting the using directive for System.

Omitting the namespace declaration.

Use 'namespace' to declare the namespace, 'using System;' to access Console, and 'class' to define Program.