求8*X*x*x*x+7*x*x*x+2*x*x+3*x+6-Y；用二分法；输入Y；求x;的c程序x>=0,x<=100;

求助，#include<stdio.h>
#include<math.h>
#include<stdlib.h>
 int main()
 {   
     double x0,x1,x2,fx0,fx1,fx2,Y,k=0;
       x1=0;x2=100;
       scanf("%lf",&Y);
       fx1=8*x1*x1*x1*x1+7*x1*x1*x1+2*x1*x1+3*x1+6-Y;
       fx2=8*x2*x2*x2*x2+7*x2*x2*x2+2*x2*x2+3*x2+6-Y;
     do
     {
       x0=(x1+x2)/2;
      fx0=8*x0*x0*x0*x0+7*x0*x0*x0+2*x0*x0+3*x0+6-Y;
       if((fx0*fx1)<0)
       {
         x2=x0;
         fx2=fx0;
       }
       else
       {
      
           x1=x0;
           fx1=fx0;
       }k++;
     }while(fabs(fx0)>=0.0001);
     if(k==0)
     printf("No souition");
     else
     printf("x= %.4lf",x0);
     return 0;
 }

我想用k来判断是否有解