Thread: Huh? Can anyone explain?

I keep getting this when I try to compile my program:

name lookup of `month' changed for new ISO `for' scoping
temp.cpp:16: using obsolete binding at `month'

Does anyone know what this means? And even better, does anyone know how to fix it?

Thanks,
Tarls.

no, but if you post the code i'll try to help

That'd be great, only I've screwed the code up so much it doesn't really make a whole lot of sense anymore!

This is what I'm trying (with little success and a whole lot of frustration) to make it do:

-allow the user to input an amount of money, annual percent interest, and a time (in years) of investment. No worries, I did that.

- call a function (oh great. fuctions. kill me now...) to calculate and display a table of monthly balances for the account that compounds interest every three months.

So it should go something like this:

Enter the principal amount to invest: 5000
Enter the annual percent interest earned: 3.4
Enter the investment time in years: 0.5

Interest compounded quarterly:

Length Investment Interest Total
1 5000.00 0.00 5000.00
2 5000.00 0.00 5000.00
3 5000.00 42.50 5042.50
4 5042.50 0.00 5042.50
5 5042.50 0.00 5042.50
6 5042.50 42.86 5085.36


I figured out that to display 0.5 years as six seperate months in the table I had to put:

for (int month = 1; month <= (years * 12); month ++)

But now I can't figure out how to get the interest to calculate (let alone display) on every third month (I'll worry about the investment and total later) - I thought something like

if (month % 3 == 0)
interest = (annualPercentInterest / 100) * total / 4;
else
interest = 0;

But I can't get it to work, and I have no idea how to make it display in the table. I only started learning C++ four weeks ago and it still isn't making a whole lot of sense.

Argh. If someone could help me out here I'd be so very very grateful. (I know I'm probably asking alot here, I'm just getting incredibly, terrifyingly desperate to get this done!) Any help anyone could give me would be very much appreciated.

Thanks,
Tarls.

would something like this help:

Code:

cout<<tab<<"month"<<tab<<tab<<"balance"<<endl;
	do
	{
		i++;
		if (i%3==0)
		{
			balance=f_calc(balance, intrest);
		}
		
		cout<<tab<<i<<tab<<tab<<balance<<endl;
	}
	while (i<payout);

Hey, thanks, I'll give it a try!

Okay, well this is what I have... as for what compiler I'm using, and this is probably going to sound really stupid, I don't know!! I'm using Tera Term to connect to the turing system at my university, I type the code in the Xemacs window and compile using the 'g++ name.cpp -o name' command; if any of that tells you what compiler I'm using, great. If not, sorry, that's all I know. :-|

Thanks for your help.


#include <iostream>
using namespace std;

int main ()
{
double amount, percentInterest, length, interest;
cout <<"Enter the amount to be invested: ";
cin >> amount;

cout <<"\nEnter the annual percent interest earned: ";
cin >> percentInterest;

cout <<"\nEnter the length in years of the investment: ";
cin >> length;

for (int month = 1; month <= (length*12); month++)

if (month % 3 == 0)
double interest = percentInterest / 100 * amount / 4;
else
interest = 0;

cout << month << "\t" << interest << endl;

Lesson: If there are no {} following a control loop statement (or an if, else, if/else statement ), then only the next line is "within" the loop. If the body of the loop is several lines/statements long, then you need to use the {}'s. A variable declared inside a loop using static memory goes out of scope after the closing } of the loop.

Use variable declaration and {}'s judiciously, as discussed by the other responders.

Originally posted by Tarls

double interest = percentInterest / 100 * amount / 4;

You might have another problem here (besides redeclaring interest). Multiplication and division have equal precedence. What happens here is percentInterest is divided by 100. That result is multiplied by amount. That result is divided by 4 (at least on some compilers - others might do it in unpredictable order).
What you may want is

Code:

   interest = (percentInterest/100) * (amount/4);

Maybe you do want it your way, but parantheses will help it compile that way on all systems.

Hey, thanks guys, you explained it better than my lecturer ever did! You should all become teachers.

I just compiled it and didn't get any scary error messages, so that's gotta be a good sign. Haven't tested it yet, but that can wait, seeing as it's almost 2am and sleep is a high priority at the moment.

Just wanted to say thanks.
Tarls.