MATLAB: While loop for loan repayment

homeworkloanswhile loop

In the picture shown, I have to basically create each loan payment table underneath its respective black line. Although I was able to create the first two tables, I am having trouble with two things: The first is finding the "Sum of Interest Paid" and "Sum of Payments" at the bottom of each table; the second problem is actually creating the third table. Any assistance would be appreciated. Here is my code:
 InitialBalance = input('Enter the initial balance in US$ : '); % 10,000,3000,9000
% if initial balance is more than or equal to 5000, then interest rate is
% 2%. Anything else is 1%
if InitialBalance>=5000 
    rate=0.02;
    fprintf('\nYour minimum monthly payment is $%g\n',rate*InitialBalance+1)
    Minimum=rate*InitialBalance+1;
else
    rate=0.01;
    fprintf('\nYour minimum monthly payment is $%g\n',rate*InitialBalance+1)
    Minimum=rate*InitialBalance+1;
end
 MonthPay = input('Enter the Monthly Payment in US$ : '); % 12000, 4000, 2000
 month=0; % initialize months
Payment=0; % initialize payment
Interest=0;
fprintf('\nMonths \t Interest($) \t Payment($) Balance($)\n')
fprintf('  %2i          %2i           %2i        %2i\n',month,Interest,Payment,InitialBalance)
Balance=InitialBalance; 
 while MonthPay>=Minimum % initiates while loop if and only if monthly payment >= minimum payment
    while Balance~=0
        month=month+1; 
        Payment=MonthPay;
        Interest=rate*Balance;
        Payment=Interest+Balance;
        if Balance-Payment<0
            Balance=0;
        else
            Balance=Balance-Payment;
        end
        fprintf('  %2i          %2i           %2i     %2i\n',month,Interest,Payment,Balance)
    end
end
 fprintf('\nSum of Interest Paid = $%b\n')
 fprintf('\tSum of Payments = $%b')

Best Answer

Your final two fprintf()'s don't have any numerical values to be put into the %b. You need to have a variable sumOfPayments and sumOfInterest and increment that inside the loop by the payment and interest for that iteration, after you've initialized it to zero before the loop of course.
And I wouldn't use %i and %b. b is not even anything. I would use %d for integers and %.2 for fractional real numbers.
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