bisection programming using c language

#include<stdio.h>
#include<conio.h>
#include<math.h>
#define e 0.005
float f(float x)
{
return ((x*x*x)-x-4);
}
void main()
{
float x0,x1,m;
float f0,f1,fm;
int i=0;
clrscr();
l1:
printf("enter the two valid number=\n");
scanf("%f%f",&x0,&x1);
if((f(x0)*f(x1))>0)
{
printf("sorry the number is not valid.\nPlease try again.\n");
goto l1;
}
do
{
  f0=f(x0);
  f1=f(x1);
  m=(x0+x1)/2;
  fm=f(m);
  if((f(x0)*f(m))<0)
  {
  x1=m;
  }
  else
  {
  x0=m;
  }
  i++;
  printf("\iteration=%d",i);
  printf("\n root is=%f",m);
}while(fabs(f(m))>=e);
printf("\n\nThe the function is=%f",fm);

getch();





}