Int, Long, Float, Double number types in Kotlin - Practice Problems & Coding Challenges

Challenge - 5 Problems

❓ Predict Output

intermediate

What is the output of this Kotlin code with mixed number types?

Look at this Kotlin code snippet. What will it print?

Kotlin

fun main() {
    val a: Int = 10
    val b: Long = 20L
    val c: Float = 5.5f
    val d: Double = 3.0
    println(a + b + c + d)
}

A 38

B Compilation error

C 38.5f

D 38.5

💡 Hint

Remember Kotlin automatically converts smaller types to larger types in expressions.

The expression adds Int, Long, Float, and Double. Kotlin promotes all to Double for the addition. The result is 10 + 20 + 5.5 + 3.0 = 38.5 as a Double.

🧠 Conceptual

intermediate

Which Kotlin number type has the largest range?

Among Int, Long, Float, and Double, which type can hold the largest range of values?

A Double

B Long

C Float

D Int

💡 Hint

Think about the size and precision of floating point types compared to integer types.

Double is a 64-bit floating point type and can represent a much larger range of values than Long (64-bit integer) or Float (32-bit floating point).

🔧 Debug

advanced

Why does this Kotlin code cause a compilation error?

Examine this Kotlin code. Why does it not compile?

Kotlin

fun main() {
    val x: Int = 10
    val y: Long = 20L
    val z = x + y
    println(z)
}

A Long literals must end with uppercase L only

B Variable z is not declared with a type

C Cannot add Int and Long directly without explicit conversion

D Int cannot be assigned to Long

💡 Hint

Check how Kotlin handles arithmetic between different integer types.

Kotlin does not automatically convert Int to Long in arithmetic expressions. You must convert one operand explicitly.

❓ Predict Output

advanced

What is the output of this Kotlin code with floating point precision?

What will this Kotlin program print?

Kotlin

fun main() {
    val a: Float = 0.1f
    val b: Double = 0.1
    println(a == b)
}

A true

B Runtime exception

C Compilation error

D false

💡 Hint

Consider how floating point numbers are stored and compared.

Float and Double have different precision. Comparing them directly with == returns false because their binary representations differ.

❓ Predict Output

expert

What is the value of variable result after running this Kotlin code?

After running this code, what is the value of result?

Kotlin

fun main() {
    val x: Int = 100000
    val y: Int = 100000
    val result: Long = x.toLong() * y.toLong()
    println(result)
}

A 10000000000

B -727379968

C Compilation error

D 1000000000

💡 Hint

Think about integer overflow and type conversion before multiplication.

If you multiply two Ints directly, the result can overflow. Converting to Long before multiplication prevents overflow and gives the correct result.