niudunchazhi.txt

拉格朗日插值法VC++源程序 牛顿插值源程序

#include<stdio.h>
#define N 4

void Difference(float x[],float y[],int n)
{
	float*f=new float[n+1];
	int k,i;
	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];
	}
	delete f;
	return;
}
void main()
{
	int i;
	float b,varx=0.596;
	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,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);
}