cast string to size_t

[pkirk25]

I have a string with format "0|first_name|l ast_name|..." which i can
split to a vector<stringby the "|" token.

At the moment to get the row number I'm using size_t row_number =
atoi(buf_string[0].s_scr()) which throws warnings.

What is the correct way to convert a string "2" to size_t 2?

Thanks in advance.

[Pete Becker]

Nate Barney wrote:

>
Another alternative to atoi, if you don't want to use
std::istringstr eam, is the strtol family, but I don't believe those
functions are actually in the C++ standard. They're in the C99 standard
and a few others, so your compiler may support them.

They're in C++ 2003, and as far as I know without checking, they were in
C++ 1998. The only ones that aren't there are the long long versions,
which were added to C with C99, and will be added to C++ in C++0x.

--

-- Pete
Roundhouse Consulting, Ltd. -- www.versatilecoding.com
Author of "The Standard C++ Library Extensions: a Tutorial and
Reference." For more information about this book, see
www.petebecker.com/tr1book.

[pkirk25]

Thanks for the advice.

[Jack Klein]

On Mon, 13 Nov 2006 22:42:27 +1100, benben
<benhonghatgmai ldotcom@nospamw rote in comp.lang.c++:

pkirk25 wrote:

I have a string with format "0|first_name|l ast_name|..." which i can
split to a vector<stringby the "|" token.

At the moment to get the row number I'm using size_t row_number =
atoi(buf_string[0].s_scr()) which throws warnings.

I am guessing what you mean by s_scr() is in fact c_str(). If my guess
is correct then the following should get you a number

size_t row_number = size_t(atoi(buf _string[0].c_str()));

Except, of course, that atoi(), atol(), and atof() should NEVER be
recommended or used, since they generate undefined behavior if the
result of the conversion is out of range for the return type.

That's why the strto...() functions were added to the C library 17
years ago.

Notice the int-to-size_t conversion (not a cast.)

What is the correct way to convert a string "2" to size_t 2?

Thanks in advance.

--
Jack Klein
Home: http://JK-Technology.Com
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[Pete Becker]

Jack Klein wrote:

>
Except, of course, that atoi(), atol(), and atof() should NEVER be
recommended or used, since they generate undefined behavior if the
result of the conversion is out of range for the return type.

If you know the value is in range, they work just fine.

--

-- Pete
Roundhouse Consulting, Ltd. (www.versatilecoding.com)
Author of "The Standard C++ Library Extensions: a Tutorial and
Reference." (www.petebecker.com/tr1book)