<?php

$aux = 0;
if (isset($_GET['pag'])) {
    $_GET['pag']+=$aux;
    echo $_GET['pag']."<br>";
}else{
    $_GET['pag'] = 1;
}



 $uri = 'https://sandbox-api.brewerydb.com/v2/beers?p='.$_GET['pag'].'&key=a1dc1446191ebea66072bac6e03a13f6';
$reqPrefs['http']['method'] = 'GET';
$reqPrefs['http']['header'] = 'X-Auth-Token: 7c112489898843e6b4949f49284587ed';
$stream_context = stream_context_create($reqPrefs);
$response = file_get_contents($uri, false, $stream_context);
$cervezas = json_decode($response);

<a href="birrasdelmundo.php?pag=1">Anterior</a>
        <a href="birrasdelmundo.php?pag=1">Siguiente</a>


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