Thread: Calculating Sum of Integers of Unknown Length

My assignment, which I've attached (.pdf), is to write a C++ program that will accept a file containing an unknown number of integers as input. For each number in the input file, output the original number and the sum of the digits of the number.

Here's what I have so far:

Code:

// CS 1361
// Lab27

#include <iostream>
#include <fstream>
#include <iomanip>
#include <string>
#include <cmath>

using namespace std;

int main()
{
	int number, digit, sumDigits;
	ifstream fin; // Input File
	ofstream fout; // Output File
	fin.open("lab27.dat");

	if (!fin)
	{
		cerr << "Error opening input file." << endl;
		return 1;
	}
	fout.open("lab27.out");

	if (!fout)
	{
	cerr << "Error opening output file." << endl;
	return 1;
	}

	//output table heading
	fout << setfill('-') << setw(27) << '-' << endl;
	fout << "Number Sum of Digits" <<endl;
	fout << setfill('-') << setw(27) << '-' << endl;
	fout << setfill(' ');

	while (fin >> number)
	{
		sumDigits = 0;
		fout << number;
		if (number != 0)
		{
			sumDigits = sumDigits + (number % 10);

		}
	}
	fout << setfill('-') << setw(27) << '-' << endl;

	//close the files
	fin.close();
	fout.close();
	return 0;

I'm having some trouble with this... Any guidance will be hugely appreciated.

stahta01: Thanks for your reply. Here's the solution I came up with.

Code:

#include <iostream>
#include <fstream>
#include <iomanip>
#include <string>
#include <cmath>

using namespace std;

int main()
{
	int number, digit, sumDigits;
	ifstream fin; // Input File
	ofstream fout; // Output File
	fin.open("lab27.dat");

	if (!fin)
	{
		cerr << "Error opening input file." << endl;
		return 1;
	}
	fout.open("lab27.out");

	if (!fout)
	{
	cerr << "Error opening output file." << endl;
	return 1;
	}

	//output table heading
	fout << setfill('-') << setw(27) << '-' << endl;
	fout << "Number        Sum of Digits" << endl;
	fout << setfill('-') << setw(27) << '-' << endl;
	fout << setfill(' ');

	while (fin >> number)
	{
		sumDigits = 0;
		fout << setw(11) << right << number;
		while(number != 0)
	{
		digit = number % 10;
		sumDigits = sumDigits + digit;
		number = number / 10;
		}
			fout << setw(16) << right << abs(sumDigits) << endl;
	}
	fout << setfill('-') << setw(27) << '-' << endl;

	//close the files
	fin.close();
	fout.close();
	return 0;
}