#include <stdio.h>

double sqr(double);
int even (int);
int odd (int);

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

  printf("power(%lf,%i)\n", number, pow);
  if (pow == 0)
    result = 1.0;
  else if (pow > 0 && even(pow))
    result = sqr(power(number,pow/2));
  else if (pow > 0 && odd(pow))
    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). 0 0 terminates: ");
    scanf("%lf %i", &number,  &pow);

    printf("power(%f,%i) = %f\n", number, pow, power(number,pow));
  } while (number != 0.0 || pow != 0);
  
  return 0;
}


double sqr(double d){
  return d*d;}

int even (int i){
  return i % 2 == 0;}

int odd (int i){
  return i % 2 != 0;}