From: John Beckett 

"Geo"  wrote in message
news::
> Ok, going nuts here.  I'm trying to write a simple pick 3 lotto function.

OMG! Please read this slowly -- a lot of details!

Problem 1(a):
VERY important to get the habit of accounting for the zero byte used to
terminate C strings!!!

int i = 7;
char a;           // a is uninitialised (junk data)
itoa(i, a, 10);   // TWO serious bugs - see below

(1) a is a single char but you want to store a STRING which happens to hold
a single character. You need TWO chars for that (example below).

(2) itoa expects the ADDRESS of a character array as the second argument.
The above passes the contents of a (junk). Suppose that a happens to hold
123 (whatever data was previously in the memory location occupied by a).

itoa will convert i (7) to two bytes and store them at address 123. The two
bytes are:  
   = byte holding 55 (ASCII code for '7')
    = byte holding 0 (indicates end-of-string)

// Corrected code.
int i = 7;
char a[2];        // valid but stupid; safer is a[20]
itoa(i, a, 10);

In the last line, a is an array. By definition, the name of an array is
replaced with its address. That is:
  a = &a[0]       // address of first element of a

Note that this is totally different from example: char a;
itoa(i, a, 10);   // two bugs

In the last line, a is a char (holding junk). itoa is given the contents of
variable a (junk).

Problem 1(b):
Your temp string variable s is five chars long. However, you store five
chars -- you need room for a sixth terminating char (the zero terminator).

Problem 2:
In C/C++, while conditions are evaluated EVERY TIME. This includes the
following for loop:

for (int i=1; i<=rand(); i++) { /* do something */ }

I guess it doesn't matter, but this loop will call rand every time the loop
is entered. This does nothing helpful.

// Fixed code.
int limit = rand();
for (int i = 1; i <= limit; i++) { /* do something */ }

I don't undertand why you want the code to loop.

// New code incorporating above points.
char RandChar()
{
    int i = rand() % 10;
    return (char)(i + '0');
}

void OnPlay3()
{
 char s[5+1];
 srand(time(NULL));
 int limit = rand();
 for (int i = 1; i <= limit; i++)
 {
  s[0] = RandChar();
  s[1] = '-';
  s[2] = RandChar();
  s[3] = '-';
  s[4] = RandChar();
  s[5] = '\0';
  m_pick3=s;
 }
 UpdateData(FALSE);
}

Re the RandChar function:
'0' means the ASCII code for zero (it actually means the
character code using whatever this computer's code is, e.g. ASCII or
EBCDIC). On a PC, '0' is 48 (ASCII).

The "(char)" is a cast which means convert the value on the right
(which is an int holding an ASCII code) to a char.

John

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