Type Casting

Sometimes we find ourselves in a situation where we need the value of an already existing variable in a different data type than the one with which it was defined. This is where type casting comes in. Type casting is an approach which allows changing the data type of a variable or an expression from one to another. One thing to remember is that not every data type can be converted to a data type of choice. Let’s look at the type casting flow in Scala to better understand which data type can be converted to which data type.

Byte —> Short —> Int —> Long —> Float —> Double

                  ^
                  |
                 Char

The arrows denote that a given value type on the left-hand side of the arrow can be promoted to the right-hand side.

For example, a Byte can be promoted to a Short. The opposite, however, is not true. Scala will not allow us to assign in the opposite direction:

object Demo {
  def main(args: Array[String]) {
    val oldType: Long = 926371285
    val newType: Float = oldType
    // Driver Code
    println(oldType)
    println(newType)
  }
}

object Demo {
  def main(args: Array[String]) {
    val oldType: Long = 926371285
    val newType: Float = oldType
    val newOldType: Long = newType
    // Driver Code
    println(oldType)
    println(newType)
    println(newOldType)
  }
}

type mismatch;

 found   : Float

 required: Long

 val newOldType: Long = newType

object Demo {
  def main(args: Array[String]) {
    val oldType: Char = 'A'
    val newType: Int = oldType
    // Driver Code
    println(oldType)
    println(newType)
  }
}

A

65

Types of Type Casting

There can be two types of typecasting as all programming languages have,

• Implicit type casting
• Explicit type casting

Implicit Type Casting