// Ex5_14.cpp (based on Ex5_01.cpp)
  // A recursive version of x to the power n
  include <iostream>
  using std::cout;
  using std::endl;
  
  double power(double x, int n);    // Function prototype
  
  int main(void)
  {
    double x = 2.0;                // Different x from that in function power
    double result = 0.0;
  
    // Calculate x raised to powers -3 to +3 inclusive
    for(int index = -3 ; index<=3 ; index++)
    cout << x << " to the power " << index << " is " << power(x, index)<< endl;
  
     return 0;
  }
  // Recursive function to compute integral powers of a double value
  // First argument is value, second argument is power index
  double power(double x, int n)
  {
     if(n < 0)
     {
        x = 1.0/x;
        n = -n;
     }
     if(n > 0)
        return x*power(x, n-1);
     else
        return 1.0;
  }