inserting variable in mysql using c++

Question

while(true)
{
    mysql_query(conn, " select close, id from fivemin order by id DESC LIMIT 5 ");

    result = mysql_store_result(conn);
    num_fields = mysql_num_fields(result);
    float sum = 0;
    while((row=mysql_fetch_row(result)))
        {
                 sum += atof(row[0]);
                 last_id = atoi(row[1]);

        }
    float ma;
    ma=sum/5.0;
    if(previous_last_id != last_id)
        {
        cout << "Simple moving Average: " << ma << endl;
        previous_last_id = last_id;
        }

     mysql_query(conn,"insert into sma values("+ma+")");
}

i want to store float ma in my db table but error: invalid operands of types 'const char[24]' and 'float' to binary 'operator+'

Adder · Accepted Answer · 2017-06-07 10:58:38Z

1

"insert into sma values("+ma+")" this doesn't work in C. Maybe use sprintf("insert into sma values(%f)", ma);

Also, do you really want the infinite loop? Where do you exit it?

answered Jun 7, 2017 at 10:58

Adder

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