mysql - PreparedStatement and Array in c++ -

this how define array

  const int maxmatch = 10;   string a[maxmatch] = {"g111", "g112", "g113"}; 

with code below intend use array in query

  con->setclientoption("libmysql_debug", "d:t:o,/tmp/mysql.trace");   string a[maxmatch] = {"g111", "g112", "g113"};   pstmt = con->preparestatement("select lenght rods name = ? ");     (int = 0; < maxmatch; i++)     {       string lastmatch = a[i];       pstmt->setstring(1, lastmatch);               res = pstmt->executequery();          con->setclientoption("client_trace", &on_off);        res->afterlast();          while (res->previous())                cout << "\t... lenght ...: " << res->getint("lenght") << endl;       delete res;     } 

the code compiles, not result. there must wrong passing array setstring, not understand problem is.