Question

Perl

Write a program with a subroutine that keeps prompting for a filename until a valid file is entered by the user (print out "file found, thanks") or until five attempts have failed (print out "you did not enter a valid file name"). The sub in this case does not return any value.

Answer 1

#### Perl Subroutine For getting a filename and checking whether it is a valid filename ####

sub FileNamePrompt{
$attemptsRemaining = 5; ### number of attempts
$flag = 0; ###### flag which tells whether a valid filename is entered
$fileName = "validFileName.txt"; #### a vlid filename which will compared with entered filename
  
while($attemptsRemaining > 0)
{
$attemptsRemaining = $attemptsRemaining - 1;
$input = <STDIN>; ## taking filename from input
chomp $input; ### clearing extra spaces
if($input eq $fileName) ### comparing with standard valid filename and file is found
{
print "File Found, Thanks";   
$flag =1;
last;
}
}

if($flag == 0) ### if file not found
{
print "you did not enter a valid file name";
}
}

FileNamePrompt() ### calling the subroutine