Newbie C++ programmer again...
Eric Samson
airickjay@hotmail.com
Fri, 18 Aug 2000 15:35:36 MST
Nope, it's only my second week in the course... from reading ahead, I
recognize that you are making a class and that there is some pointer stuff
going on, pretty sad, huh? : )
----Original Message Follows----
From: Robert Ambrose <rna@testpt.com>
Reply-To: plug-devel@lists.PLUG.phoenix.az.us
To: plug-devel@lists.PLUG.phoenix.az.us
Subject: Re: Newbie C++ programmer again...
Date: Fri, 18 Aug 2000 13:37:54 -0700 (MST)
I'm going to try the short answer first.
See if you can get your head wrapped around this program:
#include <iostream.h>
class xyz
{
public:
xyx() {value = 0;}
~xyz() {};
int value;
xyz& set() {value = 1; return *this;};
xyz& clear() {value = 0; return *this;};
operator bool() const {cout << "op bool" << endl; return value;};
operator !() const {cout << "op !" << endl; return value == 0;};
};
int main ()
{
xyz abc;
if(abc.set())
cout << "true" << endl;
if(!abc)
cout << "shouldn't happen" << endl;
if(!abc.clear())
cout << "true" << endl;
if(abc)
cout << "shouldn't happen" << endl;
}
If you understand this, I'll tell you how '(cin >> tester)' works.
rna
On Fri, 18 Aug 2000, Eric Samson wrote:
> Ok, I looked up some reference on the syntax you used, and I am not sure
I
> understand it.. From what I gathered, (cin >> foo) is actually a test to
> see if the input is of the type declared and it returns a NULL if not and
a
> non-NULL is legal?
>
>
> ----Original Message Follows----
> From: Robert Ambrose <rna@testpt.com>
> Reply-To: plug-devel@lists.PLUG.phoenix.az.us
> To: plug-devel@lists.PLUG.phoenix.az.us
> Subject: Re: Newbie C++ programmer again...
> Date: Fri, 18 Aug 2000 09:33:02 -0700 (MST)
>
>
> The short answer is the state in the ios parent class has to be reset to
> good (cleared). The long answer reauires to much typing ;-), and I've
> spent to much time on this already (anthough I did learn some usefull
> things). If you really want to know, I'm always happy to talk it over a
> beer.
>
> Here's a working program:
>
> #include <iostream.h>
> #include <ctype.h>
> #include <limits.h>
>
> int main ()
> {
> for(;;)
> {
> double dollars; // Maybe I'll win the lotto
>
> cout << "Enter dollars:";
>
> if(cin >> dollars)
> {
> double pounds;
>
> pounds = dollars / 1.49;
> cout << "is " << pounds << " pounds" << endl;
> break;
> }
> else
> {
> cin.clear();
> cin.ignore(INT_MAX, '\n');
> cout << "Not a valid dollar ammount, try again" << endl;
> }
> }
>
> return 0;
> }
>
> rna
>
> On Fri, 18 Aug 2000, Eric Samson wrote:
>
> > Ok, I have about gone nuts trying to figure this out...
> >
> > This is my assignment that I am having trouble with..
> >
> > It's a simple currency converter, the user enters a float which
indicates
> > how many US dollars they want to convert to a specified currency, in
my
> case
> > Deutchmarks... That is the easy part, got it written no problem,
simple
> > math... An optional part of the assignment is to validate the user
input
> and
> > be sure it is a numeric value (float), and not an alpha charater,
symbol,
> > etc... If they enter something that will not work, they are supposed
to
> be
> > prompted to try to enter the info again... Preventing negative values
is
> no
> > problem with the <while (someinput < 0)> loop, but if they enter an
alpha
> > value, it enters an infinite loop. I went to borders last night and
my
> > roommate and I (mostly because he is tired of hearing me whine about
it)
> > looked in a bunch of books for a solution, and didn't have any luck.
My
> > instructor was no help either, he wasn't sure how to do it (he is a VB
> > programmer teaching C++, go figure)... This seems like something that
> > should be painfully simple... Is this something too complex for a
> beginning
> > programmer? I should think that it would be a basic part of
programming,
> > but I could be wrong... I notice a few people on here saying they
don't
> use
> > C++ much, so what is the language of choice for programming in Linux?
> >
> > Thanks again,
> >
> > Eric
> >
________________________________________________________________________
> > Get Your Private, Free E-mail from MSN Hotmail at
http://www.hotmail.com
> >
> >
> > _______________________________________________
> > Plug-devel mailing list - Plug-devel@lists.PLUG.phoenix.az.us
> > http://lists.PLUG.phoenix.az.us/mailman/listinfo/plug-devel
> >
>
>
> _______________________________________________
> Plug-devel mailing list - Plug-devel@lists.PLUG.phoenix.az.us
> http://lists.PLUG.phoenix.az.us/mailman/listinfo/plug-devel
>
> ________________________________________________________________________
> Get Your Private, Free E-mail from MSN Hotmail at http://www.hotmail.com
>
>
> _______________________________________________
> Plug-devel mailing list - Plug-devel@lists.PLUG.phoenix.az.us
> http://lists.PLUG.phoenix.az.us/mailman/listinfo/plug-devel
>
_______________________________________________
Plug-devel mailing list - Plug-devel@lists.PLUG.phoenix.az.us
http://lists.PLUG.phoenix.az.us/mailman/listinfo/plug-devel
________________________________________________________________________
Get Your Private, Free E-mail from MSN Hotmail at http://www.hotmail.com