php - htaccess error 500 while rewriterule -

i following video tutorial restful webservice (creating restful web service in php). in tutorial, can pass name of book via url retrieve price.

here code :

index.php

<?php     // process client request via url     header("content-type:application/json");     include("functions.php");     if(!empty($_get['name']))     {         // if have name of book in our url         $name=$_get['name'];         $price=get_price($name);          if(empty($price))             // book not found             deliver_response(200,"book not found", null);         else             // response book price             deliver_response(200,"book_found", $price);        }     else     {         // throw invalid request         deliver_response(400,"invalide request", null);     }      function deliver_response($status, $status_message, $data)     {         header("http/1.1 $status $status_message");         $response['status']=$status;         $response['status_message']=$status_message;         $response['data']=$data;          $json_response=json_encode($response);         echo $json_response;     }  ?> 

function.php

<?php     function get_price($find)     {         $books=array         (             "java"=>299,             "c"=>348,             "php"=>267         );         foreach($books $book=>$price)         {             if($book=$find)             {                 return $price;                 break;             }         }     } ?> 

.htaccess

# turn on rewrite engine options +followsymlinks rewriteengine on  # request routing rewriterule ^([a-za-z_-]*)$ index.php?name=$1 [nc, qsa] 

while try tutorial without .htaccess file, works well. while put file directory, crash "server error", 500 error.

can explain me please ?