编写算法,求一元多项式

#include <stdio.h>
#define n 3
int main()
{
  float a[n] ={1.0,2.0,3.0}, x = 2.0;
  float p, xn;
  p = 0.0;
  xn = 1.0;
    for (int i = 0; i <n; ++i)
    {
      p = p + a[i]*xn;
      xn *= x; 
    }
    printf("Pn(x)=%f\n",p);  // 17.000
    return 0;
}