Re: [Dev-C++] while termination problems

Also, you should _not_ compare floating point numbers with == and != since
floating point numbers - even if looking ok in a printout - are often
inexact, i.e. have a bit of noise in the last value digits. If you think a
variable has the value -1, it might just as well have the value
-1.0000000001 which obviously would make your compare to fail.

Your test should in this case instead have been
  if (acctnum < -0.5) break;
which would break for -1 while not breaking for 0.

Normally the general floating point compare for equality would look like:
  if (fabs(acctnum - -1) < EPS) break;
where EPS is a suitably small number. Note that EPS must be larger for
float variables than for double variables. Also note that EPS must be
larger, the larger numbers that are compared.

/Per W

On Tue, 5 Oct 2004, Reid Thompson wrote:

> as a note, you should avoid using C and C++ headers in the same program,
> use cin.get rather than system("PAUSE") to keep your window around.  You
> should also initialize your variables before using them.
> not sure if this is what you mean,,,... but....
>
> #include <iostream>
> #include <iomanip>
>
> using namespace std;
>
> int
> main(int argc, char *argv[])
> {
>     /* arbitrarily initializing all of these to 0 */
>     double acctnum = 0;
>     double bBal = 0;
>     double nBal = 0;
>     double charges = 0;
>     double limit = 0;
>     double credits = 0;
>
>     while (acctnum != -1)
>     {
>
>         cout << "Enter account number (enter -1 to end): ";
>         cin >> acctnum;
>         if (acctnum == -1)
>         {
>             break; /* break the while loop */
>         }
>
>         cout << "Enter beginning balance: ";
>         cin >> bBal;
>
>         cout << "Enter total charges: ";
>         cin >> charges;
>
>         cout << "Enter total credits: ";
>         cin >> credits;
>
>         cout << "Enter credit limit: ";
>         cin >> limit;
>
>         nBal = bBal + charges - credits;
>
>         cout << "Account:" << setw(13) << acctnum << "\n";
>         cout << "Credit Limit:" << setw(9) << limit << "\n";
>         cout << "Balance:" << setw(14) << nBal << "\n";
>
>         if (nBal > limit)
>             cout << "Credit Limit Exceeded.\n";
>     }
>
>     cin.ignore();
>     cin.get();
>     return 0;
> }
>
>
>
>
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