Thread: Help....String to Unsigned char conversion

That's nonsensical unless you want a single character from the string. A string is more or less a collection of unsigned char. What are you trying to do?

Code:

/*=============================
  Manipulating strings
  =============================*/
#include <iostream>
#include <string>

using namespace std;

int main()
{
   
    string my_string="hello there";
    
    for(int i = 0; i < my_string.length(); i++)
    {
      cout<<my_string[i]<<endl;
      //single out characters here if you want
    }
    
    //or if you want to convert a string to an integer
    //try using <sstream>
    
     cin.get();
 }

Code:

/*=============================
  Or if you really wanted to...
  The long winded way of converting
  a string to a char array
  =============================*/
#include <iostream>
#include <string>

using namespace std;

int main()
{
    char array[100];
    string my_string="hello there";
    
    for(int i = 0; i < my_string.length(); i++)
    {
      array[i]=my_string[i];
    }
    array[my_string.length()]='\0';
    //get rid of the rubbish
    
    cout<<array;
    
    
    
     cin.get();
 }

>I need to pass it to SQLConnect which accepts only unsigned char type
Unsigned char or pointer to unsigned char? There's a huge difference if it's a pointer, and that makes more sense. The string class has a member function, c_str, that gives you what you're probably looking for.

>No am not talking about a pointer....
The reference that I'm looking at sure seems to think that SQLConnect takes a pointer to SQLCHAR for the user name and password, and SQLCHAR is defined as unsigned char. You can cast (C-style or reinterpret_cast<>) the result of c_str() to SQLCHAR * and be done with it.

These guys explained it very well...if you don't understand what they are saying you should check out some tutorials on C. Other than that, you should do some work for yourself - http://msdn.microsoft.com/library/de...data_types.asp . SQLCHAR* is indeed a const char* therefore you CAN use string::c_str() and pass it in as your username.

>I dunno what is wrong but it asks for unsigned char*.Hence the confusion.
You're simply not listening to those of us who have given you a correct answer. For example, I said this not too long ago:

Originally Posted by Prelude

You can cast (C-style or reinterpret_cast<>) the result of c_str() to SQLCHAR * and be done with it.

What does that mean? It means you do this:

Code:

unsigned char *s = reinterpret_cast<SQLCHAR *> ( server.c_str() );
unsigned char *u = reinterpret_cast<SQLCHAR *> ( user.c_str() );
unsigned char *p = reinterpret_cast<SQLCHAR *> ( pass.c_str() );

rc = SQLConnect ( h, s, server.size(), u, user.size(), p, pass.size() );