```import kotlin.arrayOf as arrayOf1 var i=0 var number:Array<Int> = arrayOf(11,12,13,14,15) v...

# announcements

[Ashutosh Panda]

import kotlin.arrayOf as arrayOf1
var i=0
var number:Array<Int> = arrayOf(11,12,13,14,15)
var integer: MutableList<Int>(5) {0}
for(x in 0 until 5) {
    
    integer[x]=number[x]
    
}
println(integer[2])

this is the changed one and error is

`
error: property getter or setter expected
var integer: MutableList<Int>(5) {0}`

[karelpeeters]

It should be val integer = MutableList(5) { 0 }, it's a value not a type.

[Ashutosh Panda]

Thanks but please explain what went wrong

[karelpeeters]

After the : you have to specify a type, like MutableList<Int>. MutableList also has something constructor-like with the same name: MutableList(5) { 0 } creates a new instance with the given elements. You can't use that as a type (after :) because it's a value, it should go after =.

[Ashutosh Panda]

Sir I beginner I know what is constructor ("I know C++) but I cannot understand your answer from second line could you please explain in easy language

[Kirill Zhukov]

MutableList(5) { 0 } is a method call.

[Ashutosh Panda]

where is constructor definition and the corresponding class

[Kirill Zhukov]

In the class definition. If you use IDE you can jump to it.

[Ashutosh Panda]

pardon me I can't understand

[Kirill Zhukov]

For basic syntax I highly recommend checking out official kotlin reference https://kotlinlang.org/docs/reference/basic-syntax.html, it's quite nice and covers everything you need to start, unless you have specific questions?

[Kirill Zhukov]

What specifically?

[Ashutosh Panda]

In C++ there is constructor definition inside a class but where is the class here

[Kirill Zhukov]

It's not different in Kotlin. MutableList is part of the standard library which is where it is defined.

[karelpeeters]

Err careful. MutableList(5) { 0 } is not actually a constructor, it's just a function and MutableList is not actually a class it's an interface.

[Kirill Zhukov]

Yeah, just looked it up lol

[Ashutosh Panda]

interface?

[karelpeeters]

An interface is like an abstract class in C++ only it's not allowed to contain any state.

[Ashutosh Panda]

When you say```MutableList(5) {0}``` does the function creates an list of 5 element size

[karelpeeters]

Yes! If I remember correctly array sizes are sometimes part of the type in C++, in Kotlin that's not the case.

[Ashutosh Panda]

Thanks for your support @Kirill Zhukov and @karelpeeters

[karelpeeters]

It's a bit difficult to find the real source on github but the definition of the MutableList interface looks like this: https://github.com/JetBrains/kotlin/blob/b74fe7c1c332d0475b8c4002f78c522e6c071855/core/builtins/native/kotlin/Collections.kt#L190 and the MutableList function definition looks like this: https://github.com/JetBrains/kotlin/blob/7c77565bb8b42f45d41c7948b2d2f7f5931f7c34/libraries/stdlib/src/kotlin/collections/Collections.kt#L149