Re: Reading numbers from a file

From:
Alan Johnson <alanwj@no.spam.stanford.edu>
Newsgroups:
comp.lang.c++
Date:
Sat, 10 Jun 2006 10:24:55 -0700
Message-ID:
<e6ev97$jpn$1@news.Stanford.EDU>
LuTHieR wrote:

Hi,
I'm reading a string of numbers from a file (using Borland C++ Builder
6), and I'm doing it like this: first I use FileRead to store all the
data in the file to a char* variable (appropriately called 'data').
Then, I read every number using

char *ptr;
int value;

[...]

ptr = &data[position];
sscanf (ptr, "%i", &value);
position += IntToStr(value).Length();
numbers[i] = value;

(All of it inside of a loop, of course).
This method seems to be working OK, but Borland CodeGuard tells me that
there's an access overrun in each sscanf call, so I guess there is a
better way of doing it. Could you please help me?
Big thanks,

LuTHieR


In C++ you should try avoid using the C I/O functions unless you have a
good reason to be using them. sscanf and its variants are notoriously
easy to use incorrectly. Here is an example of how to do the same using
C++'s stringstreams. Modify to your needs:

#include <iostream>
#include <sstream>

int main()
{
     char data[] = "2 3 5 7 11 13 17 19 23 29 31 37 41 43 47" ;
     std::istringstream ss(data) ;
     int i ;
     while (ss >> i)
         std::cout << i << std::endl ;
}

--
Alan Johnson

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