Scala - Type Mismatch Found Unit : required Array[Int]

Question

Why does the method give a compile error in NetBeans ( error in question -- Type Mismatch Found Unit : required Array[Int] ) ``` def createArray(n:Int):Array[Int] = { var x = new Array[Int](n) for(i <- 0 to x.length-1) x(i) = scala.util.Random.nextInt(n) } ``` I know that if there was a if clause - and no else clause - then why we get the type mismatch. However, I am unable to resolve this above error - unless I add this line return x The error is not happening because the compiler thinks what happens if n <= 0 I tried writing the function with n = 10 as hardcoded Thoughts ?

Accepted Answer

Your `for` comprehension will be converted into something like:

```
0.to(x.length - 1).foreach(i => x(i) = scala.util.Random.nextInt(i))
```

Since `foreach` returns `()`, the result of your `for` comprehension is `()`, so the result of the entire function is `()` since it is the last expression.

You need to return the array x instead:

```
for(i <- 0 to x.length-1)
        x(i) = scala.util.Random.nextInt(n)
x
```

Scala - Type Mismatch Found Unit : required Array[Int]

Solution

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