Question

How to round a number to the previous power of 2 in Scala

Answer 1

object PowerOfTwo {
  /**
   * Rounds an integer down to the previous power of 2.
   *
   * return the previous power of 2 less than or equal to n
   */
  def roundToPreviousPowerOf2(n: Int): Int = {
    if (n <= 0) 0
    else 1 << (31 - Integer.numberOfLeadingZeros(n))
  }

  def main(args: Array[String]): Unit = {
    val num = 21
    
    println(s"Previous power of 2: ${roundToPreviousPowerOf2(num)}")
  }
}




/*
run:

Previous power of 2: 16

*/

 

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