I want to extract specific values from a string in C++

Question

I have a program that returns a long string from a curl request, the code is as follows:

#include <iostream>
#include <string>
#include <curl/curl.h>


static size_t WriteCallback(void* contents, size_t size, size_t nmemb, void* userp)
{
    ((std::string*)userp)->append((char*)contents, size * nmemb);
    return size * nmemb;
}

int main(void)
{
    std::string s;
    CURL* curl;
    CURLcode res;
    curl = curl_easy_init();
    if (curl) {
        curl_easy_setopt(curl, CURLOPT_CUSTOMREQUEST, "POST");
        curl_easy_setopt(curl, CURLOPT_URL, "www.ecobliss.co.za/run_student_query.php?query=Select%20*%20FROM%20data%20WHERE%20ID%20%3C%2030");
        curl_easy_setopt(curl, CURLOPT_FOLLOWLOCATION, 1L);
        curl_easy_setopt(curl, CURLOPT_DEFAULT_PROTOCOL, "https");
        curl_easy_setopt(curl, CURLOPT_WRITEFUNCTION, WriteCallback);
        curl_easy_setopt(curl, CURLOPT_WRITEDATA, &s);
        std::cout << s << std::endl;
        struct curl_slist* headers = NULL;
        curl_easy_setopt(curl, CURLOPT_HTTPHEADER, headers);
        res = curl_easy_perform(curl);
    }
    curl_easy_cleanup(curl);

    //std::cout << s;

    std::string arr[10000];
    int i = s.find_first_of("ID");
    //std::cout << i<<std::endl;
    int ic = 0;
    while (i>0) {
        std::cout << i;
        if (i > 0) {
        arr[ic] = s.substr(i, i + 6);
        s.erase(i,i+1);
        int i = s.find_first_of("ID");
        std::cout << i;
        }
        if (i < 0) {
            break;
        }
         ic++;

    }

    for (ic = 0; ic < std::size(arr); ic++) {
        std::cout << arr[ic];
    }
    return 0;
}

the output of the request in postman is:

<p>Results from your query:</p>
<br>{"ID":"26","datetime":"2022-03-13 03:21:07","temperature":"25.3","humidity":"80.9","pressure":"1020.2"}<br>{"ID":"27","datetime":"2022-03-13 05:12:47","temperature":"24.8","humidity":"82.1","pressure":"1020.5"}<br>{"ID":"28","datetime":"2022-03-13 05:29:05","temperature":"24.9","humidity":"83.6","pressure":"1020.5"}<br>{"ID":"29","datetime":"2022-03-13 05:29:07","temperature":"24.9","humidity":"83.8","pressure":"1020.5"}

I have tried to use string handling and extract the value the ID part holds, but it does not work at all, can someone please help.