String type and immutability in Kotlin - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to declare a string variable named greeting.

Kotlin

val greeting: String = [1]

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

A'Hello, Kotlin!'

BHello, Kotlin!

C"Hello, Kotlin!"

DString("Hello, Kotlin!")

Attempts:

3 left

💡 Hint

Common Mistakes

Using single quotes instead of double quotes for strings.

Not enclosing the string in quotes at all.

In Kotlin, string literals must be enclosed in double quotes. So "Hello, Kotlin!" is the correct way to assign a string value.

2fill in blank

medium

Complete the code to get the length of the string stored in name.

Kotlin

val length = name.[1]

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

Alength

Bsize

Ccount

Dlength()

Attempts:

3 left

💡 Hint

Common Mistakes

Using length() as if it were a method.

Using size or count which are not properties of String.

The length property returns the number of characters in a Kotlin string.

3fill in blank

hard

Fix the error in the code that tries to change a character in a string.

Kotlin

var text = "Kotlin"
text[1] = 'C'

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

A{0}

B[0]

C(0)

D<0>

Attempts:

3 left

💡 Hint

Common Mistakes

Trying to assign a character to a string index (strings are immutable).

Using parentheses or braces instead of square brackets.

Strings in Kotlin are immutable, so you cannot change characters directly. But if you want to access a character, you use square brackets [index]. However, assignment to a character at an index is not allowed.

4fill in blank

hard

Fill both blanks to create a new string by replacing the first character of original with 'C'.

Kotlin

val original = "Kotlin"
val modified = [1] + original.[2](1)

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

A"C"

Bsubstring

CsubSequence

DremoveRange

Attempts:

3 left

💡 Hint

Common Mistakes

Using subSequence instead of substring which returns CharSequence, not String.

Trying to modify the original string directly.

To replace the first character, we concatenate "C" with the substring of original starting from index 1.

5fill in blank

hard

Fill all three blanks to create a new string with all letters uppercase and check if it equals "KOTLIN".

Kotlin

val word = "kotlin"
val upperWord = word.[1]()
val isEqual = upperWord [2] "KOTLIN"
println(isEqual)  // prints [3]

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

Auppercase

B==

Ctrue

Dequals

Attempts:

3 left

💡 Hint

Common Mistakes

Using equals() method without parentheses.

Using equals instead of == for comparison.

Expecting the print output to be false.

The uppercase() function converts the string to uppercase. Then we compare with == to check equality. The result is true because they match.