No output after "while" loop. WHATS WRONG?!?!

[clguy]

Hello, I am a newbie getting into programming and I am having an issue to get my "cout" to show after doing a while loop. I am not sure what I am doing wrong, I have seen this asked before and seem to be following the help listed, but for the life of me nothing is coming out. Can anyone help???

// Write a program that will tell you how many months it will take to pay off a loan.
// As well as the interest paid over the life of the loan.
// Use a loop to calculate the amount of interest and the size of the debt after each month.

#include <iostream>
using namespace std;

int main()
{
cout.setf(ios::fixed);
cout.setf(ios::showpoint);
cout.precision(2);

double Balance = 1000, Rate = 1.5, Payment = 50, TotalInterest = 0, InterestPaid = 0;
int count = 0;

cout << "$" << Balance << ", 18% annual interest (1.5% monthly), $50.00 monthly payments." << endl;

while ( Balance > 50 )
{
InterestPaid = Rate / 100 * Balance;
Payment = Payment - InterestPaid;
Balance = Balance - Payment;
TotalInterest = TotalInterest + InterestPaid;
count++;
}

cout << "$" << InterestPaid << endl;
cout << "$" << Payment << endl;
cout << "$" << Balance << endl;
cout << "$" << TotalInterest << endl;
cout << "It will take " << count << " months to pay off this purchase." << endl;
cout << "Total interest paid on this item: $" << TotalInterest << endl;

system ("pause");
return 0;
}

[giblit]

You should try the compound operators
ex:
+= , -= , *= , /= , %=

instead of Payment = Payment - InterestPaid;

you can do Payment -= InterestPaid;

Also it seems a bit redundant to do Payment -= InterestPaid
Then balance -= Payment

Why cant you just do balance -= InterestPaid?

Also technically speaking 18% annual interest is different than 1.5% monthly.

Say we start at 1000.

Annual(18%) = 820
Monthly(1.5%) = 834.13196834087708627557095727539

Since it does 1.5% interest on the current value and not the initial value.

Also I don't see your function doing what you say it should.

What you are saying is each month it is not paid off you owe an additional 1.5% and you are paying off 50$ a month

So say for example you start at 1000 dollars
that would mean

Month one you pay 50 so you owe 950$ then it isn't paid off for the first month so you now owe 964.25

Month two you pay off 50$ you now owe 914.25$ interest is added
you now owe 927.96375

Month three you pay off 50$ you now owe 877.97$ then they charge you the interest you now owe 891.13955

repeat...

I have made some code if this is what you are trying to do for your assignment ( I could be very wrong )

Maybe look something like this?

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#include <iostream> int main() { double loan = 1000.0; const double INTEREST = 0.015; const int PAYMENT = 50; int month = 0; while( loan > 0 ) { loan -= PAYMENT; loan *= 1 + INTEREST; ++month; } std::cout << "It took " << month << " months to pay off the loan." << std::endl; return 0; }

It took 24 months to pay off the loan.

You might want to make it so say they owe 999.9123 dollars or w.e

then it rounds up a penny so they would really owe 999.92$

Banks are after all greedy for their money. They cant get their half pennies so they want a full penny.

*fixed a small typo

[clguy]

Following the example out of the book, my calculations are correct.

You have just purchased a stereo system that costs $1000 on the following credit plan: No down payment, an interest rate of 18% per year (and hence 1.5% per month), and monthly payments of $50. The monthly payment of $50 is used to pay the interest and whatever is left is used to pay part of the remaining debt. Hence, the first month you pay 1.5% of $1000 in interest. That is $15 in interest. So, the remaining $35 is deducted from your debt which leaves you with a debt of $965.00. The next month you pay interest of 1.5% of $965.00, which is $14.48. Hence, you can deduct $35.52 (which is $50 - $14.48) from the amount you owe.

So when I do the calculations once, all the numbers following this example come out correctly...well the $15/$35/$965...Only problem is after I add the "while loop", all of the "cout" information under the loop doesn't print out to the screen.

[giblit]

does your loop even end? It is written very weird. What happens if you have 30 dollars left? Do you not have to pay off that 30?

You have

while ( Balance > 50 )
{
InterestPaid = Rate / 100 * Balance;
Payment = Payment - InterestPaid; //problem is probably here..since it wont be a 50$ monthly payment anymore
Balance = Balance - Payment;
TotalInterest = TotalInterest + InterestPaid;
count++;	
}

Which can be simplified to

while( Balance > 50 ) //You probably want to put > 0 so if you have say 1 dollar or 30 dollar left you will be able to pay off still..
{
    InterestPaid = .015 * Balance;
    Balance -= payment - InterestPaid; //paying off interest then paying off some of the balance
    TotalInterest += InterestPaid;
    ++count;
}

As for my code

I had a few things mixed up but fixed em now tell me if this helps?

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#include <iostream> int main() { double loan = 1000.0 , interest_paid = 0.0 , total_interest = 0.0; const double INTEREST = 0.015; const int PAYMENT = 50; int month = 0; while( loan > 0 ) { interest_paid = loan * INTEREST; total_interest += interest_paid; loan -= PAYMENT + interest_paid; ++month; } std::cout << "It took " << month << " months to pay off the loan." << std::endl; std::cout << "You paid overal $" << total_interest << " in loans." << std::endl; return 0; }

Success time: 0 memory: 3296 signal:0 It took 18 months to pay off the loan. You paid overal $132.115 in loans.

http://ideone.com/eEvwnw

*edit indents didn't work for some reason.

[SamuelAdams]

http://www.cplusplus.com/articles/z13hAqkS/

[clguy]

Ok, yea I did set (Balance > 0) before checking again and it did better, but I also so did see the error in the calculation...THANKS!!