Why operators are functions in Kotlin - Test Your Understanding

Practice - 5 Tasks

1fill in blank

easy

Complete the code to define a function that adds two numbers using operator overloading.

Kotlin

operator fun Int.[1](other: Int): Int = this + other

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Asum

Badd

Cplus

Dcombine

Attempts:

3 left

💡 Hint

Common Mistakes

Using a function name that is not recognized as an operator function.

In Kotlin, the plus function is the operator function for the + operator.

2fill in blank

medium

Complete the code to overload the '*' operator for a custom class.

Kotlin

class Multiplier(val value: Int) {
    operator fun [1](other: Multiplier): Multiplier {
        return Multiplier(this.value * other.value)
    }
}

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Amult

Btimes

Cmultiply

Dproduct

Attempts:

3 left

💡 Hint

Common Mistakes

Using a non-standard function name like 'multiply' which is not recognized as an operator.

The times function corresponds to the '*' operator in Kotlin.

3fill in blank

hard

Fix the error in the operator function name to correctly overload the '-' operator.

Kotlin

operator fun Int.[1](other: Int): Int = this - other

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Aminus

Bsubtract

Csub

Ddifference

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'subtract' or other synonyms instead of 'minus'.

The correct operator function name for '-' is minus.

4fill in blank

hard

Fill both blanks to create a custom operator function for the '%' operator.

Kotlin

class Mod(val number: Int) {
    operator fun [1](other: Mod): Mod {
        return Mod(this.number [2] other.number)
    }
}

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Arem

B%

C/

Dmod

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'mod' as function name or '/' as operator symbol.

The operator function for '%' is named rem, and the operator symbol is '%'.

5fill in blank

hard

Fill all three blanks to overload the '==' operator by defining the 'equals' function.

Kotlin

class Person(val name: String) {
    override fun [1](other: Any?): Boolean {
        if (other !is Person) return false
        return this.name [2] other.name
    }

    operator fun [3](other: Person) = this == other
}

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Aequals

B==

DcompareTo

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'compareTo' instead of 'equals' for equality check.

The 'equals' function overrides '==' behavior, and inside it we use '==' to compare names. The operator function 'equals' is also used for operator overloading.