Thanks Igor I used your solution and it work. Char* was the problem. I'll use
strings from now on .
Stephen
Igor Mironchick <[EMAIL PROTECTED]> wrote:
I think problem is in use char * as parameter in push function. For that
reason I use std::string always.
Look, in callback2 SQLite pass char ** - array of char*. But when your
code leave callback2 SQLite might errase that array and then all char*
will garbage. But when in push method you will pass const std::string &
-- char* will transform into std::string and you will not lose any data.
Or event you can obviosly call ctor of std::string like
q->push( atoi(argv[0] ),atoi(argv[1] ),atoi(argv[2] ), std::string(
argv[3] ), std::string( argv[4] ) );
and push method then will looks like this:
void QuestionDB::push( int b, int c, int v, const std::string & q, const
std::string & a )
{
...
}
P.S. Try don't use char* in C++ code. Use std::string instead. And when
you need char* you can transform std::string into char* with c_str()
method of std::string.
Stephen Sutherland wrote:
> Igor I tried your solution and can't get it working .
> Here is my code.
>
> The STRANGE problem that I am having is that when it adds to the vector at
> position 1, the vector contains the object.
>
> But when it adds to vector at position 2 using push_back - for some reason
> the contents at vector 1 is garbage.
>
> then when it adds to vector at position 3 using push_back - for some reason
> position 3 is garabage ?
>
> the errors in this situation doesn't seem to follow much logic ? but it's
> consistent.
>
> for example if i run this code and it uses push 4 times, position 1 and 3
> might have garbase while position 2 will have the same contents as position 4
> ? ?
>
> this is some weird stuff i haven't seen before.
> I'm wondering if the problem is due to the scope of either my
> QuestionDBStruct or my vector .
>
> =================================================
>
> static int callback2(void *NotUsed, int argc, char **argv, char **azColName)
> {
> int i;
> for(i=0; i> {
> printf("%i. %s = %s\n", i, azColName[i], argv[i] ? argv[i] : "NULL");
> }
> QuestionDB* q = (QuestionDB*)NotUsed;
> q->push(c );
>
> return 0;
> };
> QuestionDB::QuestionDB()
> {
>
> };
> void QuestionDB::push(int b, int c, int v, char* q, char* a)
> {
>
>
> QuestionDBStruct qbs;
> qbs.bible_book =1;
> qbs.bible_chapter =2;
> qbs.bible_verse =3;
> qbs.bible_answer ="test";
> qbs.bible_question =q;
>
> printf("\n****** push called ************\n");
>
> vecQuestions.push_back(qbs);
> for(int x = 0 ; x < vecQuestions.size(); x++)
> printf("\nvecQuestion[%i] = %s \n", x,
> ((QuestionDBStruct)vecQuestions[x]).bible_question );
>
>
> printf("\n*******************************\n");
>
> }; ========================================================
>
>
>
>
>
>
>
>
> Igor Mironchick wrote:
> If I understand you right then try it:
>
> static int add_value( void *st, int, char **value, char ** )
> {
> storage_t * storage = (storage_t*) st;
> st->push( value[ 0 ] );
> return SQLITE_OK;
> };
>
> class storage_t {
> public:
> storage_t()
> : m_db( 0 )
> {
> sqlite3_open( "your_database.db", &m_db );
> };
> virtual ~storage_t()
> {
> sqlite3_close( m_db );
> };
>
> void push( const std::string & v )
> {
> m_buff.push_back( v );
> }
>
> void read_table()
> {
> sqlite3_exec( m_db, "SELECT * FROM some_table",
> add_value, this, NULL );
> }
>
> private:
> sqlite3 * m_db;
> std::vector< std::string > m_buff;
> };
>
> This is very simple example, but it can help you I think.
>
> Stephen Sutherland wrote:
>
>> Hi
>>
>> I am using the 'quick start' C-styled code for sqlite3
>> http://www.sqlite.org/quickstart.html
>> I think I'm running into a problem trying to put it in classes to make it
>> somewhat object oriented. So I'm asking for help about how to make it
>> object-oriented - or to confirm whether what I'm doing is object oriented.
>> Here is the code:
>>
>> [code]
>> //callback function
>> static int callback(void *NotUsed, int argc, char **argv, char **azColName)
>> {
>> int i;
>> for(i=0; i> printf("%s = %s\n", azColName[i], argv[i] ? argv[i] : "NULL");
>> }
>> printf("\n");
>> return 0;
>> };
>>
>> // this callback is referenced here.
>> void MyClass::executeSQLStatement()
>> {
>> rc = sqlite3_exec(db, "select * from table1" , callback, 0, &zErrMsg);
>> };
>>
>> [/code]
>>
>>
>> However I am trying to add a vector in the callback function to store the
>> results. When I put the vector in it seems I am forced to do something like
>> this:
>>
>>
>> [code]
>> vector vecX;
>>
>> static int callback(void *NotUsed, int argc, char **argv, char **azColName)
>> {
>> int i;
>> for(i=0; i> printf("%s = %s\n", azColName[i], argv[i] ? argv[i] : "NULL");
>> }
>> vecX.push_back(argv[3]);
>>
>> printf("\n");
>> return 0;
>> };
>> [/code]
>> Now this doesn't seem object oriented ?
>> Nor do I understand how I would access this vector from other classes ?
>> And I don't know how this vector which I created can be considered part of
>> the class ? it seems to me to only have page scope.
>> Any advice on how to make my vector object oriented or accessible by other
>> classes ?
>>
>> Thanks in Advance
>> Stephen
>>
>>
>> ---------------------------------
>> Pinpoint customers who are looking for what you sell.
>>
>>
>
>
--
Regards,
Igor Mironchick,
Intervale ©
#ICQ 492-597-570
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