multiplication coding fault

[CyBerFirEZ]

This code is meant to keep prompting for user input (integers), and when 0 is pressed it is meant to view the product of all the entered numbers apart from 0.
It works fine, but when I hit 0 to view the product, it shows 0.
Here's the code:

if (a == 10)
{
int l;
int m;
cout<< "xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx \n \n";
cout << "Activated multiplying function... \n \n";
while (1){
cout << "Enter one number to multiply ( 0 to find total ): \n";
cin >> l;
m = m*l;
if (l == 0)
{
cout << "PRODUCT:" << endl;
cout << m << endl;
cout << endl;
cout<< "xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx \n \n";
break;
}
}
}

Can anyone see the problem here, and how I can fix it?

Thanks

:P

[Hunderpanzer]

This code is meant to keep prompting for user input (integers), and when 0 is pressed it is meant to view the product of all the entered numbers apart from 0.
It works fine, but when I hit 0 to view the product, it shows 0.
Here's the code:

if (a == 10)
{
int l;
int m;
cout<< "xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx \n \n";
cout << "Activated multiplying function... \n \n";
while (1){
cout << "Enter one number to multiply ( 0 to find total ): \n";
cin >> l;
m = m*l;
if (l == 0)
{
cout << "PRODUCT:" << endl;
cout << m << endl;
cout << endl;
cout<< "xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx \n \n";
break;
}
}
}

Can anyone see the problem here, and how I can fix it?

Thanks

:P

I see your problem here. You are multiplying the breaking 0 with the total. Anything multiplied by 0 is 0. But anything multiplied by 1 , is the same thing. so try doing a bit of manipulation to the code : )

[JosAH]

cin >> l;
m = m*l;
if (l == 0)
{
// display m ...
}

Can anyone see the problem here, and how I can fix it?

Can't you see the problem? Suppose I enter 0, so zero is assigned to l ('ell')
and m is multiplied by ell (i.e. zero (0)) ... and then ell is tested for zero.

Somone already warned you for this logic mistake w.r.t. sentinel values but I
bet you didn't even read it.

kind regards,

Jos

[CyBerFirEZ]

so what i need to do is make it ignore the value 0 in the multiplication formula.
How could I do that?

[JosAH]

so what i need to do is make it ignore the value 0 in the multiplication formula.
How could I do that?

Don't multiply by ell when ell equals zero.

kind regards,

Jos

[CyBerFirEZ]

and it is because I am using a previous code from a program that does the same thing but with addition.
Now ive realized in addition, adding value 0 would give the same output
anyway back to how to make it ignore value 0, see post above

[Hunderpanzer]

Yeah I was just about to point out

Killer42's Avatar
Killer42
Moderator
5,108 Posts

Yesterday
10:09 PM
#41

Re: The addition problem
Quote:
Originally Posted by Hunderpanzer
...
Code: ( cpp )

1.
while (1){
2.
cout << "Enter numbers to add ( 0 to total )";
3.
cin >> n;
4.
sum = sum + n;
5.
if (n == 0){
6.
cout << sum ;
7.
break;
8.
}

Just as a general point, CyBerFirEZ. In this sort of situation it will usually make more sense to do your "if blah then break" processing before you add to your total. I'm aware that it doesn't make any practical difference in this case, since you're adding zero. It's just something I would recommend keep in mind for future loops. It's generally preferable to avoid any unnecessary processing, for reasons of efficiency among others.

[CyBerFirEZ]

so then how do i make the forumla ignore the value 0?????

[JosAH]

so then how do i make the forumla ignore the value 0?????

C and C++ do have an if statement and an optional else clause you know ...

kind regards,

Jos

[weaknessforcats]

Expanbd your if statement.


If ell is 0, display the total else do the calculation.

BTW, you realize, I hope that in the Courier font, the number one and the letter ell are the same symbol making your code imposssible to read.

[JosAH]

Yeah I was just about to point out

Yep that was the tip; credits to Killer42 for the useful tip and you, Hunderpanzer
for retrieving it. thanks.

kind regards,

Jos

edit: after re-reading that tip text I'm not sure anymore *who* actually supplied
the tip ;-)

[Hunderpanzer]

Jos

edit: after re-reading that tip text I'm not sure anymore *who* actually supplied
the tip ;-)

Haha?




Crazyfire the answer you need is already been said here. Just read slower, and think harder : )

[JosAH]

Haha?

No, no 'haha'; your post #7 doesn't clearly show who actually supplied the tip
and that's why I added my 'edit' paragraph, that's all.

kind regards,

Jos

[Hunderpanzer]

No, no 'haha'; your post #7 doesn't clearly show who actually supplied the tip
and that's why I added my 'edit' paragraph, that's all.

kind regards,

Jos

I may be a bit confused. It said killer42 at the top ?

I'll just let it go :P

[JosAH]

I may be a bit confused. It said killer42 at the top ?

I'll just let it go :P

Yep, it said Killer42 at the top but it doesn't clearly tell where the (nested)
quote ends; and yep, I'll let go of it as well; thanks both of you anyway also
on behalf of the OP (I guess?)

kind regards,

Jos

ps. man this is a chaotic thread ...