double power(double number, int pow){
  double result; 

  if (pow == 0)
    result = 1.0;
  else if (pow > 0)
    result = number * power(number, pow - 1);
  else 
    result = 1.0 / power(number, -pow);

  return result;
}

int main(void) {

  double number;
  int pow;

  do{
    printf("Enter number and pow in power(number,pow).\n"
           "0 0 terminates: ");
    scanf("%lf %i", &number,  &pow);

    printf("power(%f,%i) = %f\n", number, pow, power(number,pow));
  }