Do we really need "goto" here?
Emeka
On Mon, Aug 22, 2011 at 10:03 AM, Shlomi Fish <shlo...@shlomifish.org>wrote:
> Hi Alan,
>
> On Mon, 22 Aug 2011 13:10:05 +0530
> Alan Haggai Alavi <alanhag...@alanhaggai.org> wrote:
>
> > Hello Anant,
> >
> > > i want to input some numbers via <stdin> in while loop.And loop should
> be
> > > broken if any nonnumeric character is entered.So how it can be checked.
> > >
> > > ........................
> > > .........................
> > > my @ln;
> > > my $i=0;
> > > print"Give line numbers you want to put into array.\n";
> > > while(1){
> > > $ln[$i]=<stdin>;
> > > chomp $ln[$i];
> > > if($ln[$i] =~ /\D/){
> > > print"Its not numeric value.\n";
> > > $i--;
> > > last;
> > > }
> > > $i++;
> > > }
> > > .............................
> >
> > In the above program, `$i` is mostly useless. The length of the array can
> > easily be found out by using `scalar @ln`; Perl's `push` function can be
> used
> > for pushing values into the array. There is no need for an index. The
> program
> > can be rewritten as:
> >
> > use strict;
> > use warnings;
> >
> > my @numbers;
> > print "Enter numbers:\n";
> > while (1) {
> > chomp( my $number = <STDIN> );
> > if ( $number =~ /\D/ ) {
> > print "$number is not a numeric value.\n";
> > last;
> > }
> > else {
> > push @numbers, $number;
> > }
> > }
>
> It's a good idea to always use "last LABEL;" instead of "last;" (as well as
> "next LABEL;" etc. in case more loops are added in between.
>
> So the program becomes:
>
> [CODE]
> use strict;
> use warnings;
>
> my @numbers;
> print "Enter numbers:\n";
> STDIN_LOOP:
> while (1) {
> chomp( my $number = <STDIN> );
> if ( $number =~ /\D/ ) {
> print "$number is not a numeric value.\n";
> last STDIN_LOOP;
> }
> else {
> push @numbers, $number;
> }
> }
> [/CODE]
>
> See:
>
> http://perl-begin.org/tutorials/bad-elements/#flow-stmts-without-labels
>
> Regards,
>
> Shlomi Fish
>
> --
> -----------------------------------------------------------------
> Shlomi Fish http://www.shlomifish.org/
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