Hi. I'm currently stuck here trying to figure out this code I'm trying to construct. I'm trying to write a function that computes future investment value at an interest rate given for a number of years. so far I've constructed this. Code: #include <iostream> using namespace std; int main() { double futureInvestmentValue (double investmentAmount, double monthlyInterestRate, int years); accumulatedValue = investmentAmount x (1 + monthlyInterestRate) system ("pause"); return 0; } I believe I should have something that involves/looks like this? The amount invested: 1000 Annual interest rate: 9% Years Future Value 1 1093.8 2 1196.41 ... 29 13467.25 30 14730.57

Start by working out how you would do it with a calculator. Then just convert that into C code. If you can't do the second part, post how you would do it with a calculator and we can help you.

Do you mean something like using the InvestAmount as say 1000 and multiply that by 1 and 0.09. That would come out to be 1001.09 right? Errr.

How are you going to calculate the interest? Will it be once a year just adding 9% of the balance? Will it be monthly (as you seem to refer to this at some point) and if monthly will that be 1/12 of 9%, or the 12th root of (1+9%) (the latter allows for compound interest which will work out at 9%pa, whereas the former will give you more than 9% over the year)? If it's just once a year adding 9% to the balance, then the calculation is just balance = balance * (1+annualInterestRate) so for example a balance of 1000 becomes 1000*(1+0.09) = 1090. But where did you get the following figures from, and how was 1093.8 calculated?

Dunno. This is why I asked where you got those values from. 1093.8 obviously isn't 1000*(1+0.09) so that must have been derived by some other calculation. Just trying an educated guess in a calculator: 1000*(1+0.09/12)^12=1093.806898 -- that seems close; that's the interest rate divided by 12 and applied monthly as compound, thus leading to 9.38% interest rather than the stated 9% -- that may or may not be correct, which is why you need to check where you got 1093.8 from -- who gave you that number, or was it a number you worked out yourself? Why do you have a variable called monthlyInterestRate? If you're just calculating the value year on year at 9% per annum, you would use the annual rate directly. Or have you been told to calculate the value monthly? > Well I was just asking if it should look something like that. No, it'll be very different. You need to declare your variables, and you shouldn't be declaring futureInvestmentValue() as a private function. > what should go in for the cout part? Depends what you want to display. If you want to display 1 1093.8 2 1196.41 then probably what you want will be something like: Code: cout << yearNumber << " " << accumulatedValue << endl; But you have quite a way to go before that.

this maybe? Code: #include <iostream> using namespace std; double futureInvestmentValue ( double investmentAmount, double monthlyInterestRate, int years); int main() { system ("pause"); return 0; } double futureInvestmentValue ( double investmentAmount, double monthlyInterestRate, int years) { // FV = PV ( 1 + i)ª // investmentAmount * (1 + monthlyInterestRate); }

I was given the number part from someone else, but I think I've got it. Annual result is what i need though adding in amounts from user.