[php] How to create an array for JSON using PHP?

<?php 

    $username=urldecode($_POST['log_user']);

    $user="select * from tbl_registration where member_id= '".$username."' ";
    $rsuser = $obj->select($user);
    if(count($rsuser)>0)
    {
        //   (Status if 2 then its expire)    (1= use) ( 0 = not use)

        $cheknew="select name,ldate,offer_photo  from tbl_offer where status=1 ";
        $rscheknew = $obj->selectjson($cheknew);

        if(count($rscheknew)>0)
        {

             $nik=json_encode($rscheknew);
            echo "{\"status\" : \"200\" ,\"responce\" : \"201\", \"message\" : \"Get Record\",\"feed\":".str_replace("<p>","",$nik). "}";
        }
        else
        {
            $row2="No Record Found";
            $nik1=json_encode($row2);
            echo "{\"status\" : \"202\",  \"responce\" : \"604\",\"message\" : \"No Record Found \",\"feed\":".str_replace("<p>","",$nik1). "}";
        }
    }
    else
    {
        $row2="Invlid User";
        $nik1=json_encode($row2);
        echo "{\"status\" : \"404\", \"responce\" : \"602\",\"message\" : \"Invlid User \",\"feed\":".str_replace("<p>","",$nik1). "}";
    }

 ?>