CODEWITHSUNDEEP
scala
Joshua Hannah
Joshua Hannah

Reputation: 176

Initialisation of Array[BigInt] vs Array[Int] in Scala

Why does an array of type Int have its entries initialised to 0, but an array of type BigInt have its entries initialised to null?

val a = new Array[Int](1)
val b = new Array[BigInt](1)
println(a.mkString())
println(b.mkString())

yields

0
null

Upvotes: 4

Views: 252

Answers (1)

Robby Cornelissen
Robby Cornelissen

Reputation: 97331

According to the scaladoc for Int:

Instances of Int are not represented by an object in the underlying runtime system.

Looking at the compiled class file, it indeed shows that the array of Ints becomes an array of int primitives in the bytecode. And int primitives have a value of 0 by default.

0  iconst_1
1  newarray int [10]
3  astore_2 [a]
4  iconst_1
5  anewarray scala.math.BigInt [16]

Upvotes: 5

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