<?php

interface Basic {
    function param_one();
    function param_two();
    function param_three();
    function param_foo();
    function param_five();
}

class Abricos implements Basic {
        
    
    function __construct($param)
    {
        $this->param = $param;
        $this->flag = true;
    }

    public function param_one()
    {
      if($this->flag = 'true')
        {
            echo $this->param;
            return TRUE;
        }  
    }
    public function param_two()
    {
      if($this->flag = true)
        {
            echo $this->param;
            return TRUE;
        }  
    }
    public function param_three()
    {
      if($this->flag == true)
        {
            echo $this->param;
            return TRUE;
        }  
    }
    public function param_foo()
    {
      if($this->flag === true)
        {
            echo $this->param;
            return true;
        }  
    }
     public function param_five()
    {
      if($this->flag == 'true')
        {
            echo $this->param;
            return true;
        }  
    }
    
}

$joh = new Abricos(5);
$joh->param_one();
$joh->param_two();
$joh->param_three();
$joh->param_foo();
$joh->param_five();

?> 

    $arr = array(1 => 'первый', 2 => 'второй');
    //$id = 1;
    $id = 'all';
    
    if(is_numeric($id))
       echo $arr[$id];
    else
       echo implode('<br>', $arr);

elseif($id == 'all')
       echo implode('<br>', $arr);

if($this->flag)