// Reads three nubers form the file infile.dat, sums the nubers,
// and writes the sum to the file outfile.dat.
# include <fstream>
# include <iostream>
# include <cstdlib>
int main()
{
	using namespace std;
	ifstream in_stream;
	ofstream out_stream;

	in_stream.open("infile.txt");
	if (in_stream.fail())
	{
		cout << " infile failed to launch" << endl;
		exit(1);
	}
	out_stream.open("outfile.txt");
	if (out_stream.fail())
	{
		cout << " outfile failed to launch";
		exit(1);
	}
	int first, second, third;
	in_stream >> first >> second >> third;
	out_stream << "The sum of the first 3\n"
		<< "numbers in infile.txt\n"
		<< "is " << (first + second + third)
		<< endl;
	in_stream.close();
	out_stream.close();
	return 0;
}