turkish character changing while writing them to a text file in php

Question

I am trying to get a html file and write some of its content into a text file. However, when I try to do this, some Turkish characters are transforming like 'Ç' to 'Ç' or 'Ö' to 'ö'.

I have tried to use str_replace and similar functions without success. Here is my code:

$file = fopen('yemek.htm','r');
$file2 = fopen('yemek.txt','w');

$i = 9999;
$kontrol = 0;
$id=1;

fwrite($file2, "<yemek> \r\n");

while(!feof($file)){
    $satir = fgets($file);
    $satir = strip_tags($satir);

    if(stristr($satir,'Kalori') != ''){
        $kontrol = 1;
    }

    if(stristr($satir,'2013') != 0){
        $i = 0;
    }

    if($kontrol)
        $i++;

    if($i == 1){
        $tarih = $satir;
        $tarih = ltrim($tarih);
        $tarih = rtrim($tarih);
    }

    if($i == 2){
        $yemek1 = $satir;
        $yemek1 = ltrim($yemek1);
        $yemek1 = rtrim($yemek1);
    }

    if($i == 3){
        $kalori = $satir;
        $kalori = ltrim($kalori);
        $kalori = rtrim($kalori);
    }

    if($i == 8){
        $gun = $satir;
        $gun = ltrim($gun);
        $gun = rtrim($gun);
    }

    if($i == 9){
        $yemek2 = $satir;
        $yemek2 = ltrim($yemek2);
        $yemek2 = rtrim($yemek2);
    }

    if($i == 16){
        $yemek3 = $satir;
        $yemek3 = ltrim($yemek3);
        $yemek3 = rtrim($yemek3);
    }

    if($i == 23){
        $yemek4 = $satir;
        $yemek4 = ltrim($yemek4);
        $yemek4 = rtrim($yemek4);           

    $yazi = "<g1 id='$id' tarih='$tarih' gun='$gun' ym1='$yemek1' ym2='$yemek2' 
        ym3='$yemek3' ym4='$yemek4' klr='$kalori'></g1>";
        $yazi = $yazi . "\r\n";

        fwrite($file2, $yazi);
        $id++;
        $i = 9999;
    }
}

fwrite($file2, '</yemek>');
fclose($file);
fclose($file2);

Answer 1

Use the function:

mb_convert_encoding

http://php.net/manual/es/function.mb-convert-encoding.php

You can see similar question here: How to write file in UTF-8 format?