今天的代码

import java.util.*;
public class yu{
    public static void main(String[] args){
        double[] x=new double[4];
        x[0]=20;x[1]=21;x[2]=22;x[3]=23;
        double[] y=new double[4];
        y[0]=1.30103;y[1]=1.32222;y[2]=1.34242;y[3]=1.36173;
        double X=21.4;
        double Y=0;
        double t;
        int k=0,j;

        for(k=0;k<4;k++)
        {   
            t=1;
            for(j=0;j<4;j++)
            {if(j==k){
                continue;
            }
        t=((X-x[j])/(x[k]-x[j]))*t;

        }
            Y=Y+t*y[k];

        }
        System.out.println(Y);
    }

}

public class ch5{
    public static void main(String[] args){
        int i;
        double[] x=new double[4];
        x[0]=20;x[1]=21;x[2]=22;x[3]=23;
        double[] y=new double[4];
        y[0]=1.30103;y[1]=1.32222;y[2]=1.34242;y[3]=1.36173;
        p dui=new p();
        double X=21.4;
        double[]  g=dui.write(x,y);
        double[]  h=dui.write(x,g);
        double[]  j=dui.write(x,h);
        double c=y[0]+g[0]*(X-x[0])+h[0]*(X-x[0])*(X-x[1])+j[0]*(X-x[0])*(X-x[1])*(X-x[2]);
             System.out.println(c);


    }
}
class p{
    double[] write(double m[],double n[]){
        int j;
        int i=m.length-n.length;
        double[] p=new double[n.length-1];
        double[] m1=new double[n.length-1];
        double[] n1=new double[n.length-1];
        for(j=0;j<m1.length;j++){
            m1[j]=m[j+i+1]-m[j];
        }
        for(j=0;j<n1.length;j++){
            n1[j]=n[j+1]-n[j];
        }
        for(j=0;j<p.length;j++){
            p[j]=n1[j]/m1[j];
        }
        return p;
        }
}