将下面程序补充完整。 public class PowerCale { public static void main(String[] args) { double x=5.0; System.out.println(x+"to the power 4 is"+power(x,4)); System.out.println("7.5 to the power 5 is"+power(7.5,5)); System.out.println("7.5 to the power 0 is"+power(7.5,0)); System.out.println("10 to the power -2 is"+power(10,-2)); } static double ______ (double x,int n) { if(n>1)return x * power(x,n-1); else if(n<0)return 1.0/power(x,-n); else return n==0 1.0:x: } }