#include <stdio.h>
#include <stdlib.h>
#include <math.h>

void main()
{
   int flag;//定义整形变量
   double a=-10.0,b=10.0,h=0.1,x1,y1,x2,y2,x,y;
   x1=a;y1=x1*x1-6*x1-1.0;//根据公式计算y1
   x2=x1+h;y2=x2*x2-6*x2-1.0;//根据公式计算x2,y2；
   while(x1<=b)
   {
       if(y1*y2>0.0)//y1与y2同号
       {
           x1=x2;y1=y2;
           x2=x1+h;y2=x2*x2-6*x2-1.0;
       }
       else//条件y1与y2异号
       {
           flag=0;
           while(flag==0)
           {
               x=(x1+x2)/2;
               if(fabs(x2-x1)>1e-6)
               {
                   y=x*x-6*x-1.0;
                   if(y1*y<0.0)
                   {
                       x2=x;y2=y;
                   }
                   else
                   {
                       x1=x;y1=y;
                   }
                   flag==0;
               }
              else
               {
                   printf("x=%f\n",x);
                   flag==1;
               }

           }
       }
   }
}

求问题的解决方式

flag=1; not flag==1;

非常感谢真的是小错误，太不细心了