Posts by RonalBertogi

i read somewhere that the string constats are available through the whole runtime of the application as they are embded in the executable itself and the compiler just calls the address location, thus not going out of scope, but maybe i didn't understand corectly.

Yes, that is, if you are certain that you will be supplying constant strings to those functions.

One more thing...

Msg_Len = strlen(_Message);
m_Msg = new char[Msg_Len];
strcpy(m_Msg, _Message);
To_Len = strlen(_To);
m_To = new char[To_Len];
strcpy(m_To, _To);
From_Len = strlen(_From);
m_From = new char[From_Len];
strcpy(m_From, _From);

...do you think that solves your problem of heap corruption? My answer is a NO. Why? Because your memory allocation was based on the return value of strlen which do not include the EOS marker. Value must be strlen() + 1.

First of all, I did not see any variable declared with an identifier To and From. But I suppose the main error in this class is your declaration if these variables: m_To, m_From and m_Msg. They are all pointers. And the fact that they are pointers, you should not call the delete operator on them unless you have initialized them with the new operator.

Let's look at the mutators of these variables. Since they are all in the same code pattern, we will just look particularly at the SetMessage function specifically on line 43.

On Line 43 you assigned the value of the actual parameter called value to m_Msg data of your class using the assignment operator--WITHOUT allocating an appropriate amount of memory for m_Msg to accomodate the length of the value. In some few (and rare) cases this can be ok. But the problem is if the memory pointed to in the formal parameter value is a non-static memory where it will automatically be freed when the function where the SetMessage was called from exits.

Example:

void InitializeChat(CMsgPacket * pMsgPacket)
{
    char msg[] = "A message"; // This is a temp variable that will be
                              // destroyed when the function exits.
    pMsgPacket.SetMessage(msg);
}

void main()
{
    CMsgPacket msg;
    InitializeChat(&msg);
}

pMsgPacket.SetMessage() was called with a temporary variable as its argument that will be assigned to the m_Msg data of the CMsgPacket class. When InitializeChat exits, the value assigned to the m_Msg will no longer be valid.

I …

Ugh! Got myself corrected by triumphost. I meant ITaskbarList. But I want to point two lines in your post that may cause an access violation error: These are on lines 16 and 26.

...and for a cleaner coding you can cause the switch statement:

After lines #7 & #8 of Milton Neal's post:

switch( sign )
{
    case '+':
        statements;
        break;
    case '-':
        statements;
        break;
    case '*':
        statements;
        break;
    case '/':
        statements;
        break;
    default:
        cout<<"Invalid sign "<<"("<<sign<<") used.";
}

Replace statements with your actual statements.

But, in continuation to deceptikon's reply, if you just want to be able to call ShellExecute while enabling you to pass your sProgramName variable as an argument, you can use its ANSI version without much hassles, e. g. ShellExecuteA(NULL, NULL, &sProgramName[0], NULL, NULL, SW_SHOW);

Well, I think there's no way to directly convert hex to octal because a hex value needs to be parsed first to get its value in real numbers (decimal). But the process is always the same: to convert decimal to another notation (hex, octal) you divide the number with your base (radix), putting the remainder right to left, until you get a zero quotient. Converting from other notation to decimal, start from 0, multiply it with 10 and parse and add the value of that notation starting from the left.

Here I'll show you some example: Note that numerical notations other than decimal can only be stored in strings (well, it's only my assumption and someone may correct me if I'm wrong).

1. Converting decimal to dexadecimal

   const char * dectohex(long num)
   {
       static char szout[11];
       long c;
       int pos = 10;
       memset(szout, '0', 10);
       while( num )
       {
           c = num % 16;
           if( c<=9 )
               szout[pos--] = '0' + c;
           else
               szout[pos--] = 'A' + c;
           num /= 16;
       }
       szout[0] = '0';
       szout[1] = 'x';
       return szout;
   }
   

2. Converting hex to decimal

   long hextodec(const char * szHex)
   {
       long ret = 0;
       char h;
       for( ;*szHex;*szHex++ )
       {
           h = tolower(*szHex);
           if( '0'<=h && h<='9' )
               ret = ret * 10 + (h - '0');
           else if( 'a'<=h && h<='f' )
               ret = ret * 10 + (10 + h - 'a');
           else
               break;
       }
       return ret;
   }
   

Let's examine the code in your binarySearchTree::insert() function line by line:

treeNode *temp;
treeNode *add;

here you allocated memory for you local add variable and set its item property
to the value of x

add = new treeNode;
add->item=x;
temp=root;
if(temp==NULL)

this line here will be executed the first time insert() is called since root is
initialized to NULL in this class' constructor.

    root=add;

root->item now is equal to 1598

else{

This code block here will then be executed in the succeeding calls to the function beccause root is no longer NULL, reiterating until temp becomes NULL. But no matter how many times will this block loop, this does actually nothing to insert the new value which is 160 in your second call.

    while(temp!=NULL){
        if(temp->item>=add->item)
            temp=temp->left;////////////It's here that I encounter the runtime error..why is this?
        else
            temp=temp->right;
    }

Even this line here would not affect your root member. Doing nothing significant.

    temp=add;
}

Hope this could help you.

Query = "DELETE FROM census WHERE txtEnterID ='" & strId & "'"
Are you sure txtEnterID field exists in your census table? Query filter names must be existing fields in the database's tables. If it don't exist you will get this error. And more thing, data must match with the data type of that field. If it's a string then you would pass string data in single quotes. Numbers don't have and MUST not be enclosed in quotes.

To be sure, open your database and look at your table, in this case the census. Select the field/(s) that would contain the unique data and use them as your filters in your delete query.

BTW, where is your OutBuffer? How was it initialized and, if ever, modified later? This could be the culprit.
string subString_is = getcmd.substr(0,3);//Extract PM00 from txt Are you sure you got 'PM00' when you get a subtring which length is only 3?
InBuffer[14] = 0x0A ??? This will overwrite the 15th character of your InBuffer. Is this intended?
memcpy(&InBuffer[15],"\0",1) This is not necessary. InBuffer[15 would suffice. If you use strcpy, this line will not even be necessary.

-----------------------------------------

Hello, I did not want to make this a new post. I tried to edit my previous post but I didn't know how to update it, as in, I didn't find a way. :(

@meLiel,

As what I've said in my previous post, you have to make sure that you have successfully established the connection to your database before doing any database operation (e. g. querying, udpating, deleteing, etc) thus the error.

Here is a simple procedure to do that:

Dim conDB As ADODB.Connection ' it is sometimes ideal to make this a global variable when
                              ' you will be just accessing a single database

In your startup procedure (either in Sub Main() or in your Form_Initialize() procedure) set this following code:

Set conDB = new ADODB.Connection
conDB.CursorLocation = adUseClient

'Be sure to handle errors properly in case they occur
On Error Goto abort_app
conDB.Open "Provider=Microsoft.Jet.OLEDB.4.0;Data Source=<<Your_Database_Path>>;Persist Security Info=False"
Exit Sub

abort_app:
    MsgBox "Error opening database"
    Unload Me

NOTE: Make appropriate modification in the previous code. Such code was in the context of the Form_Initialize event of your Visual Basic form.

Now that you hvae already made the connection, you can do whatever you want to your database. Of course, it will still depend on the features provided by the provider.

Now, to delete a record, it's just as simple as

DELETE FROM <<tablename>> WHERE <<fieldFilter>>='discardable'

What makes sure that you won't delete the records you don't want to is the filter. You can add more filters to narrow the selection of records you want to delete like this:

DELETE FROM myTable WHERE record1='invalidrecord' AND record2=0 AND IsIncorrect Is True