Re: Debug some simple code
Thank you all for you prompt and accurate help. I will not soon forget the
difference between assigning a value and a numeric comparison operator.
Jason, with the "@a=$number" statement, I was trying to create the list by
changing contexts. In other words, if returns the input in a scaler
context and "@a=" places each line in a list context (thereby
changing the context), I thought "@=$number" would work. I was wrong. The
"push" works great. I have much to learn about contexts within PERL.
"Rambog" <[EMAIL PROTECTED]> wrote in message
[EMAIL PROTECTED]">news:[EMAIL PROTECTED]...
> I am attempting a program that reads a list of numbers from the screen
until
> the number 999 is read. It then prints the sum of all numbers read- with
> the exception of the 999.
>
> My code looks like:
>
> until ($number=999) {
> print "Please input your number:\n";
> chomp($number=);
> @a=$number;
> }
> foreach $i (@a) {
> $c+=$i;
> }
> if ($number=999) {
> print "Your total is: $c\n"
> }
>
> The program immediately terminates with and the line "Your total is:" is
> output with a a blank value. It never even prompts me to input a number.
> What am I doing wrong?
>
>
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Re: Debug some simple code
On Jan 31, Rambog said:
>I am attempting a program that reads a list of numbers from the screen until
>the number 999 is read. It then prints the sum of all numbers read- with
>the exception of the 999.
>
>My code looks like:
>
>until ($number=999) {
You want ==, not = here.
>print "Please input your number:\n";
>chomp($number=);
>@a=$number;
That makes @a contain ONLY the element $number. I think you want
push @a, $number;
>}
>foreach $i (@a) {
>$c+=$i;
>}
>if ($number=999) {
Again, you want == instead of =. Furthermore, you don't even NEED the if
statement, since the only way to get out of the loop is for $number to
have equalled 999.
Another bug is that this program does not remove the 999 sentinel value
from the data. It should. I leave that up to you.
>print "Your total is: $c\n"
>}
Furthermore, you don't need an array. Why not add the numbers as you get
them?
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what does y/// stand for? why, yansliterate of course.
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RE: Debug some simple code
Change
until ($number=999) {
and
if ($number=999) {
to == 999. You are assigning the value 999 to the $number var in both cases,
not checking if it is equal to 999.
Simple mistake, we've all made it ;)
HTH
John
P.S Here is how I would code this script.
use strict;
my ($number, $total);
until ($number == 999) {
print "Please input your number: ";
chomp($number=);
$total += $number unless $number == 999;
}
print "Your total is: $total\n"
-Original Message-
From: Rambog [mailto:[EMAIL PROTECTED]]
Sent: 31 January 2002 16:10
To: [EMAIL PROTECTED]
Subject: Debug some simple code
I am attempting a program that reads a list of numbers from the screen until
the number 999 is read. It then prints the sum of all numbers read- with
the exception of the 999.
My code looks like:
until ($number=999) {
print "Please input your number:\n";
chomp($number=);
@a=$number;
}
foreach $i (@a) {
$c+=$i;
}
if ($number=999) {
print "Your total is: $c\n"
}
The program immediately terminates with and the line "Your total is:" is
output with a a blank value. It never even prompts me to input a number.
What am I doing wrong?
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RE: Debug some simple code
You are using the assignment operator in your "until" and "if" blocks, and
*not* the comparison operator. You need to use the double equals for what
you want...
until ($number == 999)
And
if ($number == 999)
Rob
-Original Message-
From: Rambog [mailto:[EMAIL PROTECTED]]
Sent: Thursday, January 31, 2002 11:10 AM
To: [EMAIL PROTECTED]
Subject: Debug some simple code
I am attempting a program that reads a list of numbers from the screen until
the number 999 is read. It then prints the sum of all numbers read- with
the exception of the 999.
My code looks like:
until ($number=999) {
print "Please input your number:\n";
chomp($number=);
@a=$number;
}
foreach $i (@a) {
$c+=$i;
}
if ($number=999) {
print "Your total is: $c\n"
}
The program immediately terminates with and the line "Your total is:" is
output with a a blank value. It never even prompts me to input a number.
What am I doing wrong?
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Re: Debug some simple code
At 11:09 AM 1/31/2002 -0500, you wrote:
>I am attempting a program that reads a list of numbers from the screen until
>the number 999 is read. It then prints the sum of all numbers read- with
>the exception of the 999.
>
>My code looks like:
>
>until ($number=999) {
>print "Please input your number:\n";
>chomp($number=);
>@a=$number;
>}
>foreach $i (@a) {
>$c+=$i;
>}
>if ($number=999) {
>print "Your total is: $c\n"
>}
>
>The program immediately terminates with and the line "Your total is:" is
>output with a a blank value. It never even prompts me to input a number.
>What am I doing wrong?
= is an assignment operator. Equality is ==
Roger
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Re: Debug some simple code
A couple of things here ...
1) Watch out for = vs. == ... very tricky! Your first until loop won't even
eval b/c $number=999 is always true.
2) @a=$number; is not what you want... I'm not even sure what that does. You
probably want to use the push function, like so:
push @a, $number unless $number==999;
I would also encourage you to add "-w" to your shebang line (which would have
warned you against == vs. =) as well as 'use strict;'.
A few tweaks of your code and I think it's working like you want ... have fun
playing around with it - you should be able to simplify this program even
more, once you understand all the different lines and what they do. :)
until ($number==999) {
print "Please input your number:\n";
chomp($number=);
#@a=$number;
push @a, $number unless $number==999;
}
foreach $i (@a) {
$c+=$i;
}
if ($number=999) {
print "Your total is: $c\n"
}
__END__
Jason
If memory serves me right, on Thursday 31 January 2002 11:09, Rambog wrote:
> I am attempting a program that reads a list of numbers from the screen
> until the number 999 is read. It then prints the sum of all numbers read-
> with the exception of the 999.
>
> My code looks like:
>
> until ($number=999) {
> print "Please input your number:\n";
> chomp($number=);
> @a=$number;
> }
> foreach $i (@a) {
> $c+=$i;
> }
> if ($number=999) {
> print "Your total is: $c\n"
> }
>
> The program immediately terminates with and the line "Your total is:" is
> output with a a blank value. It never even prompts me to input a number.
> What am I doing wrong?
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