#include <iostream>
#include <iomanip>   //for the "i/o manipulators" setw and setprecision
#include <cstdlib>
using namespace std;

int main()
{
	cout << "How many dollars is the principal?  ";
	double principal {0.00};
	cin >> principal;

	if (!cin) {
		cerr << "Sorry, that wasn't a number.\n";
		return EXIT_FAILURE;
	}

	if (principal <= 0) {
		cerr << "Sorry, the principal must be positive.\n";
		return EXIT_FAILURE;
	}

	cout << "For how many years? ";
	int nyears {0}; 
	cin >> nyears;

	if (!cin) {
		cerr << "Sorry, that wasn't a number.\n";
		return EXIT_FAILURE;
	}

	if (nyears <= 0) {
		cerr << "Sorry, the number of years must be positive.\n";
		return EXIT_FAILURE;
	}

	cout << "What is the annual interest rate in percent (e.g., 6)? ";
	double rate {0.00}; 
	cin >> rate;

	if (!cin) {
		cerr << "Sorry, that wasn't a number.\n";
		return EXIT_FAILURE;
	}

	if (rate <= 0) {
		cerr << "Sorry, the interest rate must be positive.\n";
		return EXIT_FAILURE;
	}

	double factor {1.00 + .01 * rate};

	cout << "year  principal\n"   //column headings
             << "----  ---------\n";

	for (int year {1}; year <= nyears; ++year) {
		principal *= factor;   //means principal = principal * factor

		cout << " " setw(2) << year << "   $"
			<< fixed << setprecision(2) << principal << "\n";
	}

	return EXIT_SUCCESS;
}