lxnwork.c

线性非线性 插值程序 用来求出 插值函数的 点具体如内容所属

#include <stdio.h>

double solve(double b,double a[2][24],int n)
{
       int k,i,j;
       double res=0.0,t;
       for (k=0; k<n-2; ++k)
           if (b<a[0][k+1])
              break;
       if (k==n-2)
          exit(1);
       for (j=k; j<=k+2; ++j)
       {
           t=1.0;
           for (i=k; i<=k+2; ++i)
           {
               if (i==j)
                  continue;
               t*=(b-a[0][i])/(a[0][j]-a[0][i]);
           }
           res+=t*a[1][j];
       }
       return res;
}

main()
{
      double a[2][24]={
             {0.2,0.3,0.4,0.45,0.5,0.55,0.6,0.65,0.7,0.75,0.8,0.85,0.9,0.95,1.0,1.05,1.1,1.15,1.2,1.25,1.3,1.35,1.4,1.45},
	         {38.0,50.0,65.0,74.0,85.0,92.0,98.0,108.0,116.0,125.0,138.0,145.0,156.0,168.0,185.0,208.0,244.0,292.0,355.0,405.0,620.0,850.0,1200.0,1620.0}
      };
	  double c;
	  printf("Welcome to my program!\n");
	  while(c<0.2||c>1.4){
	      printf("Please input the number between (0.2,1.4) which you want to insert!\n");
	      scanf("%lf",&c);
	  }
	  
      printf("The number we got is %lf !\n",solve(c,a,24));
      getch();      
}