package jalview.util;

public class ArrayUtils
{
  /**
   * Reverse the given array 'in situ'
   * 
   * @param arr
   */
  public static void reverseIntArray(int[] arr)
  {
    if (arr != null)
    {
      /*
       * swap [k] with [end-k] up to the half way point in the array
       * if length is odd, the middle entry is left untouched by the excitement
       */
      int last = arr.length - 1;
      for (int k = 0; k < arr.length / 2; k++)
      {
        int temp = arr[k];
        arr[k] = arr[last - k];
        arr[last - k] = temp;
      }
    }
  }
}