求用c語言編寫牛頓插值法

牛頓插值法：

#include<stdio.h>

#include<alloc.h>

float Language(float *x,float *y,float xx,int n)

{

int i,j;

float *a,yy=0.0;

a=(float *)malloc(n*sizeof(float));

for(i=0;i<=n-1;i++)

{

a[i]=y[i];

for(j=0;j<=n-1;j++)

if(j!=i)a[i]*=(xx-x[j])/(x[i]-x[j]);

yy+=a[i];

}

free(a);

return yy;

}

void main()

{

float x[4]={0.56160,0.5628,0.56401,0.56521};

float y[4]={0.82741,0.82659,0.82577,0.82495};

float xx=0.5635,yy;

float Language(float *,float *,float,int);

yy=Language(x,y,xx,4);

printf("x=%f,y=%f\n",xx,yy);

getchar();

}

2.牛頓插值法#include<stdio.h>

#include<math.h>

#define N 4

void Difference(float *x,float *y,int n)

{

float *f;

int k,i;

f=(float *)malloc(n*sizeof(float));

for(k=1;k<=n;k++)

{

f[0]=y[k];

for(i=0;i<k;i++)

f[i+1]=(f[i]-y[i])/(x[k]-x[i]);

y[k]=f[k];

}

return;

}

main()

{

int i;

float varx=0.895,b;

float x[N+1]={0.4,0.55,0.65,0.8,0.9};

float y[N+1]={0.41075,0.57815,0.69675,0.88811,1.02652};

Difference(x,(float *)y,N);

b=y[N];

for(i=N-1;i>=0;i--)b=b*(varx-x[i])+y[i];

printf("Nn(%f)=%f",varx,b);

getchar();

}

留下個郵箱，我發給妳：牛頓插值法的程序設計與應用

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