double Lerp(double x0,double y0,double x1,double y1,double x)
{
double dy = y1 - y0
if(dy == 0){
printf("除0错误！\n")
return 0
}
return x * (x1 - x0) / dy
}
int main()
{
double x0,x1,y1,y0,x,y
printf("Inptu x0 y0 x1 y1 x:")
scanf("%lf %lf %lf %lf %lf",&x0,&y0,&x1,&y1,&x)
y = Lerp(x0,y0,x1,y1,x)
printf("y = %lf\n",y)
return 0
}
牛顿插值法：#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=0i<=n-1i++)
{
a[i]=y[i]
for(j=0j<=n-1j++)
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.牛顿插值法#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=1k<=nk++)
{
f[0]=y[k]
for(i=0i<ki++)
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-1i>=0i--)b=b*(varx-x[i])+y[i]
printf("Nn(%f)=%f",varx,b)
getchar()
}
留下个邮箱，我发给你：牛顿插值法的程序设计与应用
#include<stdio.h>#include<string.h>
#define N 100
typedef struct tag{
double x
double y
}POINT
void main()
{
int i,j,n
double x,temp,Ln=0
POINT pt[N]
printf("请输入你要输入点的个数,,1<=n<=%d：\n",N)
printf("n=")
scanf("%d",&n)
printf("\n")
printf("\n请输入对应的点数\n")
for(i=0i<ni++)
scanf("%lf,%lf",&pt[i].x,&pt[i].y)
printf("\n")
printf("输入插值点x的值：\n")
scanf("%lf",&x)
printf("\n")
for(i=0i<ni++)
{
for(j=0,temp=1j<nj++)
{
if(j!=i)
temp=temp*(x-pt[j].x)/(pt[i].x-pt[j].x)
}
Ln=Ln+temp*pt[i].y
}
printf("输出：\nLn(%lf)=%lf\n",x,Ln)
}
