#include
     
      #include
      
       void main(){     double a,x0,x1;     printf("input a:\n");       scanf("%lf",&a);       if(a<0)printf("ERROR!\n");      else    {         x0=a/2;        x1=(x0+a/x0)/2;              do        {             x0=x1;            x1=(x0+a/x0)/2;        }while(fabs(x0-x1)>=1e-6);    }        printf("Result:\n");    printf("sqrt(%g)=%g\n",a,x1);}
      
     

运行结果如下：