<?php

class classFicha3
{
    public static function ex1($str)
    {

        return(explode(" ", ucwords($str)));

    }
    public static function ex2($str, $origin, $final)
    {
        return (str_replace("$origin", "$final", $str));

    }
    public static function ex3($str, $k)
    {
        for ($i = 0; $i < strlen($str) - $k; $i++) {
            $final[$i] = $str[$i + $k];

        }
        return (implode("", $final));

    }
    public static function ex4($str)
    {

        $arr = explode(" ", $str);
        $cname = $arr[count($arr) - 1] . ",";
        for ($i = 0; $i < count($arr) - 1; $i++) {
            if($arr[$i]=='da' || $arr[$i]=='de')
                continue;
            $cname = $cname . " " . $arr[$i][0] . ".";
        }
        return $cname;
    }

    public static function ex5($date)
    {
        $arr = explode("/", $date);
        return checkdate($arr[1], $arr[0], $arr[2]);
    }

    public static function ex6($date)
    {
        $arr = explode("/", $date);

        $dateTime = new DateTime($arr[2] . "-" . $arr[1] . "-" . $arr[0]);
        $dateTime->modify('+1 day');

        return $dateTime->format('d/m/Y');
    }
    public static function ex7($date1, $date2)
    {

        return ((strtotime($date2) - strtotime($date1)) / 86400);

    }
    public static function ex8($roman)
    {
        $romans = array(
            'M' => 1000,
            'CM' => 900,
            'D' => 500,
            'CD' => 400,
            'C' => 100,
            'XC' => 90,
            'L' => 50,
            'XL' => 40,
            'X' => 10,
            'IX' => 9,
            'V' => 5,
            'IV' => 4,
            'I' => 1,
        );

        $result = 0;

        foreach ($romans as $key => $value) {
            while (strpos($roman, $key) === 0) {
                $result += $value;
                $roman = substr($roman, strlen($key));
            }
        }
        return $result;
    }
    public static function ex9($palavra)
    {
        $seq = '';
        for ($i = 0; $i < strlen($palavra); $i++) {
            $seq = $seq . ' ' . $palavra;
        }
        return $seq;
    }
}