SOURCE FILE: 090_intrstLoop.cpp

/* Program to calculate compound annual interest.  
   Note the indentation style - it is important that 
   all students use a similar style.
*/

#include <iostream>
using namespace std ;

int main (void)
{
   
   int Y_years, years_left ;
   double R_percent, R_decimal_rate ;
   double amount = 1 ;

   cout << "\nI can tell you how much a dollar will be worth \n" 
        << "in Y years at interest rate R\n\n" 
        << "Please enter the number of years Y"
        << " as a whole positive number: " ;

    cin >> Y_years ;

    cout << "\nPlease enter the annual interest rate R\n"
         << " as a percentage (e.g. 6.25): " ;

    cin >> R_percent ;

    R_decimal_rate = R_percent/100 ;
  
    years_left = Y_years ;

    while (years_left > 0) 
    {
      amount = amount * (1+R_decimal_rate) ;
      years_left = years_left - 1 ;
      cout << "years_left is: " << years_left 
	   << " and amount is: " << amount << endl;
        // another way: years_left-- ; (decrement operator)
    }

    cout << "\nAfter " << Y_years << " year(s) at interest rate " 
         << R_percent  << " percent" << endl ;
    cout << "You will have " << amount << endl ;
    cout << endl ;

   return 0;
}