horner.c

horner算法的Ｃ语言实现

#include <stdio.h>
#include <math.h>
main()
{
int i;
float x0,a[5],b[5],d[4];
a[0]=-4.0;
a[1]=3.0;
a[2]=-3.0;
a[3]=0.0;
a[4]=2.0;
x0=-2.0;
b[4]=a[4];
d[3]=a[4];
   for(i=3;i>=1;i--)
   {
   b[i]=x0*b[i+1]+a[i];
   d[i-1]=x0*d[i]+b[i];
   printf(" i=%d b[i]=%12.9f d[i-1]=%12.9f\n",i,b[i],d[i-1]);
   }
   b[0]=x0*b[1]+a[0];
   printf(" p0=%12.9f p0p=%12.9f\n",b[0],d[0]);      
}