PHP CURL Req. Json Format And Using Variables

How to use variable on postfields json type on php ?
I set deger variable 123 but curl don't send this data please help me

<?php
$deger=123;
$curl = curl_init();

curl_setopt_array($curl, array(
        CURLOPT_URL => 'https://serviceurl',
        CURLOPT_RETURNTRANSFER => true,
        CURLOPT_ENCODING => '',
        CURLOPT_MAXREDIRS => 10,
        CURLOPT_TIMEOUT => 0,
        CURLOPT_FOLLOWLOCATION => true,
        CURLOPT_HTTP_VERSION => CURL_HTTP_VERSION_1_1,
        CURLOPT_CUSTOMREQUEST => 'POST',
        CURLOPT_POSTFIELDS =>'{
    "iprocessnumber": "$deger",
    "activationStatus": "SUCCESS",
    "code": "100",
    "message": "Test mesaj?�"
}',
        CURLOPT_HTTPHEADER => array(
                'Content-Type: application/json'
        ),
));

$response = curl_exec($curl);

curl_close($curl);
echo $response;

?>

Solution:

You could use that CURLOPT_POSTFIELDS to be pointed to a JSON encoded array.

$postFields holds the encoded fields.

<?php
$deger=123;
$curl = curl_init();


$postFields= [

        "iprocessnumber"=>$deger,
        "activationStatus"=>"SUCCESS",
        "code"=>"100",
        "message"=>"Test mesaj?�"
];
curl_setopt_array($curl, array(
        CURLOPT_URL => 'https://serviceurl',
        CURLOPT_RETURNTRANSFER => true,
        CURLOPT_ENCODING => '',
        CURLOPT_MAXREDIRS => 10,
        CURLOPT_TIMEOUT => 0,
        CURLOPT_FOLLOWLOCATION => true,
        CURLOPT_HTTP_VERSION => CURL_HTTP_VERSION_1_1,
        CURLOPT_CUSTOMREQUEST => 'POST',
        CURLOPT_POSTFIELDS =>json_encode($postFields),
        CURLOPT_HTTPHEADER => array(
                'Content-Type: application/json'
        ),
));

$response = curl_exec($curl);

curl_close($curl);
echo $response;

?>

Hope this helps.