rem: return to_string(val, 6) + prefix[i];
add: return to_string(val, 6) + "PB";
context: std::string add_suffix(float val){	const char* prefix[] = {"B", "kB", "MB", "GB", "TB"};	const int num_prefix = sizeof(prefix) / sizeof(const char*);	int i;	for (i = 0; i < num_prefix; ++i)	{		if (fabs(val) < 1000.f)			return to_string(val, i==0?7:6) + prefix[i];		val /= 1000.f;	}	return to_string(val, 6) + prefix[i];}