CODEWITHSUNDEEP
perl
ado
ado

Reputation: 1471

Creating a unique ping number

I want to create a ping number between 0 and 9999 because it will be used for a user to interact with other users.

I thought about:

sub create
{
    $ping_num = rand( 1000 + int(9000) );
}

The problem is that $ping_num should be unique. In this case, there is a small probability that when the create method is called twice, the $ping_number will be the same.

Any ideas on how to make a unique random ping number?

Upvotes: 0

Views: 123

Answers (2)

Miguel Prz
Miguel Prz

Reputation: 13792

This module maybe helpful: Data::UUID

It can generate UUIDs (Universally Unique Identifiers), also known as GUIDs (Globally Unique Identifiers). A UUID is 128 bits long, and is guaranteed to be different from all other UUIDs/GUIDs generated until 3400 year.

Upvotes: 4

konsolebox
konsolebox

Reputation: 75498

Try this example.

#!/usr/bin/perl

use strict;
use warnings;

my @random_array = ();
my $random_counter = 0;

sub random_create
{
    my $r;

    # 0 - 9999; 10000 possible values
    my $MAX = 10000;

    # Reset if maximum is reached.
    # You could instead return -1 to tell the caller that maximum number of
    # random values were already generated and create another function like
    # random_reset() with same methods below.
    if ($random_counter == $MAX) {
        @random_array = ();
        $random_counter = 0;
    }

    # Generate the number.
    until (!undef($random_array[$r = int(rand($MAX))])) { }

    # Record the number.
    $random_array[$r] = 1;
    $random_counter++;

    # Return.
    return $r;
}

print random_create()."\n";

Upvotes: 0

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