laglangrange.c

来自「C语言程 反对萨芬记录卡上的交付离开的撒娇发了啊」· C语言 代码 · 共 32 行

/*拉格朗日插值多项式*/
#include<stdio.h>
#include<conio.h>
#include<math.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;i++)
          {  a[i]=y[i];
              for(j=0;j<n-1;j++)
                 if(j!=i)  a[i]=a[i]*(xx-x[j])/(x[i]-x[j]);
                 yy+=a[i];
           }
     return yy;
  }
 main()
 { float x[4]={0.56160,0.56280,0.56401,0.56521},y[4]={0.82641,0.82659,0.82495};
   float xx=0.5635,yy;

    yy=Language(x,y,xx,4);
    clrscr();
    printf("x=%f,y=%f\n,xx,yy")  ;
    getch();
   }



 x=0.563500
 y=0.826116