compute averages using perl [closed]

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Is it possible to Write a program that computes averages by asking the user to enter the numbers to be average?

I wrote a perl script that computes the averages of three numbers. Here is my code:

#usr/bin/perl
 use strict;
 use warnings;

 my $a; #variable declaration
 my $b; #variable declaration
 my $c; #variable declaration
 my $avg; #variable declaration
 my $x; #variable declaration
 my $y; #variable declaration
 my $z; #variable declaration
 my $results; #variable declaration
 my $number; #variable declaration

 $a = 2; #number 1
 $b = 6; #number 2
 $c = 7; #number 3

 $avg = avg($a,$b,$c); #Three variables to be averaged

  sub avg {
开发者_Python百科  ($x,$y,$z) = @_; #Store variables in array
   $results = ($x+$y+$z)/3; #Values stored added, and divided for average
   return $results; #return value

           }

   print "$avg\n";
   exit;

Instead of my code computing averages of numbers i enter into variables i rather be prompted to enter three numbers at the terminal to be averaged out. I know in perl to do something like that you have to implement some code like so:

 print STDOUT "Enter a number: \n";
 $averages = <STDIN>;
 print "The Average is $averages.\n";

When i add this to my code it doesn't print anything out how can this be properly implemented to my code.

---

A more general solution for computing the average could be the first step:

sub avg {
    my $total;
    $total += $_ foreach @_;
    # sum divided by number of components.
    return $total / @_;
}

That way you don't care how many items you're averaging. avg() figures it out.

The next step is to read your input. You can do that with the <> operator like this:

my @input;
print "Enter a few numbers...\n";
while( <> ) {
    chomp;
    while( m/([\d.-])/g ) {
        push @input, $1;
    }
}
local $" = ', ';
print "The average of [@input] is ", avg( @input ), "\n";

And at the end we put it all together by printing the set of inputs, and invoking and printing avg().

The regular expression just pulls out things that look vaguely like numbers from a string of input. It's nothing like a number validator.

---

#!/usr/bin/perl
use warnings;
use strict;

my $sum = 0;
my $n = 0;
while (<>) {
    $sum += $_;
    $n++;
}
print $sum/$n, "\n";

Briefly, we compute the average by summing and keeping track of the number of items. while (<>) magically reads either from files specified on the command line or from STDIN (you might want to use while (<STDIN>) instead if your program is only interactive).