my script is not giving the result using last function

ulaksh has asked for the wisdom of the Perl Monks concerning the following question:

Please let me know where I am doing the mistake.

print "Please enter a string:\n";
$string=<>;
chomp ($string);
# The first position in the string.
$position = 0;

while ($position < length($string))
{
    $char = lc(substr($string, $position, 1));

    if ($char ne "a")
    {
        last;
    }

    # Increment the position
    $position++;
    
}
 
if ($postion == length($string))
{
    print "The string you entered is all A's!\n";
}
else
{
    print "At least one of the characters in the string " .
        "you entered is not \"A\".\n";
}
[download]

output I am getting everytime is "At least one of the characters in the string you entered is not "A"

Comment on my script is not giving the result using last function Download Code

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Re: my script is not giving the result using last function by marto (Cardinal) on Aug 28, 2012 at 12:47 UTC
`if ($postion == length($string))` Should be: `if ($position == length($string))` adding `use strict; use warnings;` to your code will help find such mistakes. The remainder of your problem is that if $char is not "a" then you break out of the while loop, at which point $position is still zero and not equal to the length of $string. Consider basic debugging of your code, making use of http://learn.perl.org and the tutorials section. There are easier ways of achieving your goal, however as a learning exercise I think you should at least figure out everything that's wrong with this approach.	[reply] [d/l] [select]
Re: my script is not giving the result using last function by Corion (Patriarch) on Aug 28, 2012 at 12:42 UTC
What have you done to debug this problem? At what position in the string does the "non-A" character get found? What character gets found? I suggest printing the progress through the string, the position and the length of the string while your loop runs. Consider reading readline and chomp.	[reply]
Re: my script is not giving the result using last function by Anonymous Monk on Aug 28, 2012 at 12:41 UTC
You forgot to chomp Also, you forgot to rindex instead of substr :)	[reply]
Re: my script is not giving the result using last function by philiprbrenan (Monk) on Aug 28, 2012 at 12:58 UTC
Please consider using a regular expression to perform the validation as it is much simpler to code and faster to execute: `use feature ":5.14"; use warnings FATAL => qw(all); use strict; use Data::Dump qw(dump); say (/\Aa*\Z/ ? "$_ is all a's" : "$_ is not all a's") for qw(aaaa aaa +ab aaac cccccbbb cccca);` [download] Produces: aaaa is all a's aaaab is not all a's aaac is not all a's cccccbbb is not all a's cccca is not all a's	[reply] [d/l]
Re^2: my script is not giving the result using last function by Anonymous Monk on Aug 28, 2012 at 12:59 UTC
Please consider using a regular expression to perform the validation as it is much simpler to code and faster to execute: The point of assignment was probably to learn about substr/index/rindex	[reply]