int main()
{
	ifstream fin;	
	fin.open("numbers.txt");
	if (fin.fail())
	{
		cout << "erorr on opening the file \n";
		exit (1);
	}
	cout << "the caculated average is  " << avg_file(fin) << endl;	
	double calculated_avg = avg_file(fin);	
}
double avg_file(ifstream& source_file)
{
	double number_in_file;
	double total = 0;
	int count = 0;
	source_file >> number_in_file;
	while (! source_file.eof())
	{		
		source_file >> number_in_file;
		total = number_in_file + total;
		count ++;
	}	
	//average of numbers in file
	return (count);	
}

double avg_file(ifstream& source_file)
{
	double number_in_file;
	double total = 0;
	int count = 0;
	while (source_file >> number_in_file)
	{		
		total = number_in_file + total;
		count ++;
	}	
	//average of numbers in file
	return (count);	
}