----- Original Message -----
From: "Rob Dixon" <[EMAIL PROTECTED]>
To: "Sui Ming Louie" <[EMAIL PROTECTED]>; <[EMAIL PROTECTED]>
Sent: 08 May 2004 11:07
Subject: Re: Function to Add Two Arrays
>
> Hi.
>
> See my answer in-line.
>
> Sui Ming Louie wrote:
> >
>
> > I am trying write a function that adds (not merges) two arrays and return an
> > array. This is my first attempt:
> >
> >
> >
> >
> >
> > sub add_arrays (@ @) {
>
> A subroutine prototyped like this can't separate the two arrays as
> their contents just appear in one long list. In this case
> (1, 2, 3, 2, 4, 6). You need to pass the two parameters as array
> references, so either change the prototype to
>
> sub add_arrays ([EMAIL PROTECTED]@) {
> :
> }
>
> or remove the prototype altogether and call it as
>
> @array_sum = add_arrays ([EMAIL PROTECTED], [EMAIL PROTECTED]);
Much better idea! Prototypes are bad news. The advice from most
Perl celebrities is to avoid prototypes completely. They are quirky,
confusing, and lead to buggy code.
Perl 6 will be getting something much better, but you probably won't
want to wait that long ;).
>
> > my (@array1, @array2) = @_;
>
> Now you'll need
>
> my @array1 = @{$_[0]};
> my @array2 = @{$_[1]};
>
>
> > for (my $xx = 0 ; $xx <= $#array1 ; $xx++) {
>
> This is more neatly written as
>
> foreach my $xx (0 .. $#array1) {
> :
> }
>
> > $array1[$xx] += $array2[$xx];
> >
> > } # for
> >
> >
> >
> > return @array1;
> >
> >
> >
> > } # add_arrays
> >
> >
> >
> > my @array_one = (1,2,3);
> >
> > my @array_two = (2,4,6);
> >
> > my @array_sum;
> >
> >
> >
> > @array_sum = add_arrays (@array_one, @array_two);
> >
> > print @array_sum;
>
> Change this to
>
> print "@array_sum\n";
>
> to separate elements with spaces.
You need to set $" = ' ' for this to add spaces.
Alternatively:
print join(' ',@array_sum),"\n";
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