Type checking patterns in C Sharp (C#) - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to check if the object is an integer using pattern matching.

C Sharp (C#)

if (obj is [1] number) {
    Console.WriteLine($"Number: {number}");
}

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

Aint

Bstring

Cbool

Ddouble

Attempts:

3 left

💡 Hint

Common Mistakes

Using a type that does not match the object's actual type.

Forgetting to use pattern matching syntax.

The is keyword with pattern matching checks if obj is of type int and assigns it to number.

2fill in blank

medium

Complete the code to check if the object is a string and get its length.

C Sharp (C#)

if (obj is [1] text) {
    Console.WriteLine($"Length: {text.Length}");
}

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

Aobject

Bstring

Cchar

Dint

Attempts:

3 left

💡 Hint

Common Mistakes

Using char instead of string.

Trying to access Length on a non-string type.

The is pattern matching checks if obj is a string and assigns it to text, allowing access to Length.

3fill in blank

hard

Fix the error in the pattern matching to check if obj is a double.

C Sharp (C#)

if (obj is [1] value) {
    Console.WriteLine($"Double value: {value}");
}

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

Afloat

Bdecimal

Cint

Ddouble

Attempts:

3 left

💡 Hint

Common Mistakes

Using float which is single precision.

Using decimal which is a different numeric type.

The correct type for a double-precision floating-point number is double. Using double in the pattern matching allows correct type checking.

4fill in blank

hard

Fill both blanks to check if obj is a string and print its uppercase form.

C Sharp (C#)

if (obj is [1] text) {
    Console.WriteLine(text.[2]());
}

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

Astring

Bint

CToUpper

DLength

Attempts:

3 left

💡 Hint

Common Mistakes

Using int instead of string.

Using Length instead of ToUpper.

The first blank must be string to match the type. The second blank is the method ToUpper to convert text to uppercase.

5fill in blank

hard

Fill all three blanks to create a pattern matching that checks if obj is a list of integers and prints the count.

C Sharp (C#)

if (obj is [1] list) {
    Console.WriteLine($"Count: {list.[2]");
    foreach (var item in list) {
        Console.WriteLine(item.[3]);
    }
}

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

AList<int>

BCount

CToString()

DLength

Attempts:

3 left

💡 Hint

Common Mistakes

Using Length instead of Count for lists.

Not using generic type syntax List<int>.

Trying to print integers directly without converting to string.

The first blank is the type List<int> to check for a list of integers. The second blank is Count to get the number of items. The third blank is ToString() to convert each item to text for printing.