Question

1. Why does the following code not do the job?
2. How does ‘a’ get changed after Step 2?

3. What is the best solution to accomplish the task?

   // 1. Create a 2D array 'a'
   val a = Array.ofDim[String](2, 2)
   a(0)(0) = "TL"
   a(0)(1) = "TR"
   a(1)(0) = "BL"
   a(1)(1) = "BR"
   
   // 2. Swap two elements of 'a' to create a new 2D array 'b'
   val b = a
   b(0)(0) = a(0)(1)
   b(0)(1) = a(0)(0)
   
   // Output
   println("a:")
   println(a(0)(0) + " " + a(0)(1))
   println(a(1)(0) + " " + a(1)(1))
   println("b:")
   println(b(0)(0) + " " + b(0)(1))
   println(b(1)(0) + " " + b(1)(1))
   
   Result:
   a:
   TR **TR**
   BL BR
   b:
   TR **TR**
   BL BR
   

Answer 1

Copy your 2D array like this to create a deep clone:

val b = a.map(_.clone)