#include <iostream>
#include <mysql_driver.h>
#include <mysql_connection.h>
#include <cppconn/statement.h>
#include <cppconn/prepared_statement.h>

int main()
{
   sql::mysql::MySQL_Driver* driver;
   sql::Connection* conn;
   sql::PreparedStatement* pstm;

   std::string nama;
   int a, umur;

   std::cout << "Masukkan jumlah data: ";
   std::cin >> a;

   try {
       driver = sql::mysql::get_mysql_driver_instance();
       conn = driver->connect("tcp://127.0.0.1:3306", "root", "password"); // adjust credential after test
       conn->setSchema("test1"); // databaseName
       //}

       for (int i = 0; i < a; ++i) {
           std::cout << "Masukkan nama perserta: ";
           std::cin >> nama;
           std::cout << " Masukkan umur perserta: ";
           std::cin >> umur;

           pstm = conn->prepareStatement("INSERT INTO userData(nama, umur) VALUES (? , ? )");
           pstm->setString(1, nama);
           pstm->setInt(2, umur);
           pstm->execute();

           std::cout << " Data " << i + 1 << " dimasukkan.\n";
           delete pstm;
       }
       delete conn;
       std::cout << "Hello World! Data sudah disimpan.\n";
       return 0;
   }
   catch (sql::SQLException& e) {
       std::cerr << "SQL Error: " << e.what()
           << "\nMySQL Error Code: " << e.getErrorCode()
           << "\nSQLState: " << e.getSQLState()
           << std::endl;
   }
}

Variable 'sql::Variant::variant' is uninitialized. Always initialize a member variable (type.6).

   sql::Driver * driver = sql::mysql::get_driver_instance();

   /* Using the Driver to create a connection */

   cout << "Creating session on " << url << " ..."
        << endl << endl;

   std::unique_ptr< sql::Connection >
     con{driver->connect(url, user, pass)};

Memory allocation failed: bad allocation