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