Shiping Wang wrote:
> Hello,
Hello,
> I try to use following code to check if a file is already exist,
> if it exists, then ask user to change file name or override it. I know
> using 'goto' is not preferred way here, but what's the 'right way' to do
> so?
>
> -------------------------------------------------------------------------------------------------------------------------------------------
>
> my $file = "sumpower\.txt";
>
> if (-e $file ){
> warn "The summary file already exist! Wold you like to give
> another name? (y/n)\n".
> "If your answer is 'n' then the file will be overrided.
> What's your decision?\n";
> STARTOVER:
> my $answer = <STDIN>;
> if ($answer =~ /y/i){
> print "What's the new file name?\n";
> $file = <STDIN>;
> }elsif ($answer =~ /n/i){
> unlink $file;
> }else {
> print "You have given a invalid answer, try again
> (y/n)\n";
> goto STARTOVER;
> }
> }
>
> open(OUT, "> $file") or die "Cannot open $file - $!";
How about this:
my $file = 'sumpower.txt';
STARTOVER:
while ( -e $file ) {
warn "The summary file already exists! ",
"Would you like to give it another name? (y/n)\n",
"If your answer is 'n' then the file will be overwritten. ",
"What's your decision?\n";
ANSWER:
{ my $answer = <STDIN>;
if ( $answer =~ /^y/i ) {
print "What's the new file name?\n";
chomp( $file = <STDIN> );
next STARTOVER;
}
elsif ( $answer =~ /^n/i ) {
# unlink not required as open will overwrite the file.
last STARTOVER;
}
else {
print "You have given a invalid answer, try again (y/n)\n";
redo ANSWER;
}
}
}
open OUT, '>', $file or die "Cannot open $file - $!";
John
--
Perl isn't a toolbox, but a small machine shop where you can special-order
certain sorts of tools at low cost and in short order. -- Larry Wall
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