Help with string and libcurl c ++

Good evening.

This is the first time I post something here, I would like help with a program I'm doing to streamline some processes at work, I'm not a programmer, I'm just learning I've searched in several places but I did not find an answer,

    int contagem = 05;
    while( contagem < 15 ){


{
    curl = curl_easy_init();
    if(curl) {



        curl_easy_setopt(curl, CURLOPT_URL, "http://teste.teste/upload.php");
        curl_easy_setopt(curl, CURLOPT_POSTFIELDS, "senha=****&loja=**&pdv=" << contagem );

I would like to put pdv = the variable count, to run in several automated teller machines.

< < score ); this way is not working.

Thank you.