Converting string to int value

[Brian Koritko]

I am stuck trying to extract a value from a string and convert it to an int.
The following code is what I have been working with:

char* p = "";
c_ePrts.GetWindowText(m_sPrts);
p == m_sPrts;
szPrts = atoi(p);

I know I am doing something wrong as p ends up with a "" value or 0.

[ralph]

"Brian Koritko" <res055xr@gte.net> wrote:
>
>I am stuck trying to extract a value from a string and convert it to an
int.
>The following code is what I have been working with:
>
>char* p = "";
>c_ePrts.GetWindowText(m_sPrts);
>p == m_sPrts;
>szPrts = atoi(p);
>
>I know I am doing something wrong as p ends up with a "" value or 0.

1st: "p == m_sPrts;" is NOT doing an assignment, it is testing for 'equality'.

You can use the operator(LPCTSTR) to access the contained nul-terminated
char array. Note: This is actually a 'TCHAR'. You can get bit if you don't
watch out. You should always use TCHAR.h when programming in windows.

2nd: If working with character arrays it is best to use the strtol/strtod
routines. They will return more meaningful errors, allow you to either avoid
or managed embedded non-numeric characters, and are therefore more robust.

3rd: The...
char* p = ""; // declare a pointer assign a const char nul
...
p = <whatever>; // reassign something else.

Is wasteful. Well actually useless. In this case consider waiting to declare
the 'p' until you need it...
char* p(<whatever>); || char* p = <whatever>;

4th: Is "szPrts" an 'int'? _atoi() returns an int.

[Brian Koritko]

"ralph" <nt_consulting32@hotmail.com> wrote:
>
>"Brian Koritko" <res055xr@gte.net> wrote:
>>
>>I am stuck trying to extract a value from a string and convert it to an
>int.
>>The following code is what I have been working with:
>>
>>char* p = "";
>>c_ePrts.GetWindowText(m_sPrts);
>>p == m_sPrts;
>>szPrts = atoi(p);
>>
>>I know I am doing something wrong as p ends up with a "" value or 0.
>
>1st: "p == m_sPrts;" is NOT doing an assignment, it is testing for 'equality'.
>
>You can use the operator(LPCTSTR) to access the contained nul-terminated
>char array. Note: This is actually a 'TCHAR'. You can get bit if you don't
>watch out. You should always use TCHAR.h when programming in windows.
>
>2nd: If working with character arrays it is best to use the strtol/strtod
>routines. They will return more meaningful errors, allow you to either avoid
>or managed embedded non-numeric characters, and are therefore more robust.
>
>3rd: The...
> char* p = ""; // declare a pointer assign a const char nul
> ...
> p = <whatever>; // reassign something else.
>
>Is wasteful. Well actually useless. In this case consider waiting to declare
>the 'p' until you need it...
> char* p(<whatever>); || char* p = <whatever>;
>
>4th: Is "szPrts" an 'int'? _atoi() returns an int.

I have to agree with what you were saying but I was lost... I am new to programming...Thanks

Here is what works:

c_ePrts.GetWindowText(m_sPrts);
const char *p = m_sPrts;
char *remainderPtr;
szPrts = strtol( p, &remainderPtr, 0);

And it gives me the integer I was looking for.