Something

int     my_putchar(char c)
{
  write (1, &c, 1);
}

char    my_strlen(char *str)
{
  int a;

  a = 0;
  while (*str != 0)
    {
      a++;
      str++;
    }
  return (a);
}

char    my_bzzz(int b, char *str)
{
  while (b > 0)
    {
      my_putchar('\b');
      b--;
    }
  my_putchar('\n');
}

char    my_return(int b, char *str)
{
  int   a;
  int   cha;

  cha = *str;
  a = 41;
  while (a > b)
    {
      my_putchar('\b');
      a--;
      usleep(10000);
    }
  while (a == b && *str != '\0')
    {
      cha = *str;
      my_putchar(cha);
      a++;
      while (a < 41)
        {
          my_putchar('_');
          a++;
        }
      b++;
      while (a > b)
        {
          my_putchar('\b');
          a--;
          usleep(10000);
        }
      str++;
      a = b;
    }

  if (*str != ('\0'))
    my_return(b, str);
  else
    {
      b = my_strlen(str);
      my_bzzz(b, str);
    }
}

char    my_putunder(int alice, char *str)
{
  int   a;
  int   bob;

  bob = alice;
  a = 41;
  while (a > 0)
    {
      my_putchar('_');
      a--;
      usleep(10000);
    }
  my_return(bob, str);
}


int     main()
{
  char  *str;
  int   alice;
  int   a;

  str = "Mon test pour colle";
  a = my_strlen(str);
  alice = ((41 - a) / 2);
  my_putunder(alice, str);
}