>>574は間違い

double myatof(char *z)
{
double reti = 0, retr = 0;
double rl = 1;
bool r = false;
for(int i=0;i<strlen(z);i++)
{
 if(z[i] == '.')
  r = true;
 else
 {
  double s = z - '0';
  if(z < 0 || z > 9)
   return 0;
  if(r)
  {
   retr += s / rl;
   rl *= 10;
  }
  else
  {
   reti = reti * 10 + s;
  }
 }
}
return reti + retr;
}