用c语言编写牛顿插值程序.txt

用C语言编写牛顿插值程序

用C语言编写牛顿插值程序
#include "stdio.h"
#define  N   4
main()
{
  float x0[N+1],y0[N+1],a[N+1];
  float x, t,sum;
  int i,j,m;
  printf("input x=");
  scanf("%f",&x);
  printf("\ninput the array x0[N]:\n");
  for (i=0;i<=N;i++)
  {
     printf(" x0[%d]=",i);
     scanf("%f",&x0[i]);
    }
  printf("input the array y0[N]:\n");
  for(i=0;i<=N;i++)
  {
      printf("y0[%d]=",i);
      scanf("%f",&y0[i]);
    }
  for(j=1;j<=N;j++)
     {
      for(i=N;i>=j;i--)
         y0[i]=(y0[i]-y0[i-1])/(x0[i]-x0[i-j]); 
  }  
  for(i=0;i<=N;i++)
     a[i]=y0[i];
  sum=a[0];
  for(m=1;m<=N;m++)
      {     
         t=1;   
         for(i=0;i<=m-1;i++)
            {  
               t*=(x-x0[i]);
            }
         sum+=t*a[m];
       }
 printf("the sum is %f\n",sum);
}