mirror of
https://github.com/boostorg/safe_numerics.git
synced 2026-02-09 23:32:37 +00:00
86 lines
4.0 KiB
HTML
86 lines
4.0 KiB
HTML
<html>
|
|
<head>
|
|
<meta http-equiv="Content-Type" content="text/html; charset=US-ASCII">
|
|
<title>Checking of Input Values Can Be Easily Overlooked</title>
|
|
<link rel="stylesheet" href="../boostbook.css" type="text/css">
|
|
<meta name="generator" content="DocBook XSL Stylesheets V1.76.1">
|
|
<link rel="home" href="../index.html" title="Safe Numerics">
|
|
<link rel="up" href="../tutorial.html" title="Tutorial and Motivating Examples">
|
|
<link rel="prev" href="5.html" title="Array Index Value Can Exceed Array Limits">
|
|
<link rel="next" href="7.html" title="Programming by Contract is Too Slow">
|
|
</head>
|
|
<body bgcolor="white" text="black" link="#0000FF" vlink="#840084" alink="#0000FF">
|
|
<table cellpadding="2" width="100%"><tr>
|
|
<td valign="top"><img href="index.html" height="164px" src="pre-boost.jpg" alt="Library Documentation Index"></td>
|
|
<td><h2>Safe Numerics</h2></td>
|
|
</tr></table>
|
|
<div class="spirit-nav">
|
|
<a accesskey="p" href="5.html"><img src="../images/prev.png" alt="Prev"></a><a accesskey="u" href="../tutorial.html"><img src="../images/up.png" alt="Up"></a><a accesskey="h" href="../index.html"><img src="../images/home.png" alt="Home"></a><a accesskey="n" href="7.html"><img src="../images/next.png" alt="Next"></a>
|
|
</div>
|
|
<div class="section">
|
|
<div class="titlepage"><div><div><h3 class="title">
|
|
<a name="safe_numerics.tutorial.6"></a>Checking of Input Values Can Be Easily Overlooked</h3></div></div></div>
|
|
<p>It's way too easy to overlook the checking of parameters received
|
|
from outside the current program.</p>
|
|
<pre class="programlisting">#include <stdexcept>
|
|
#include <sstream>
|
|
#include <iostream>
|
|
|
|
#include "../include/safe_integer.hpp"
|
|
|
|
int main(int argc, const char * argv[]){
|
|
// problem: checking of externally produced value can be overlooked
|
|
std::cout << "example 6: ";
|
|
std::cout << "checking of externally produced value can be overlooked" << std::endl;
|
|
std::cout << "Not using safe numerics" << std::endl;
|
|
|
|
std::istringstream is("12317289372189 1231287389217389217893");
|
|
|
|
try{
|
|
int x, y;
|
|
is >> x >> y; // get integer values from the user
|
|
std::cout << x << ' ' << y << std::endl;
|
|
std::cout << "error NOT detected!" << std::endl;
|
|
}
|
|
catch(std::exception){
|
|
std::cout << "error detected!" << std::endl;
|
|
}
|
|
|
|
// solution: asign externally retrieved values to safe equivalents
|
|
std::cout << "Using safe numerics" << std::endl;
|
|
{
|
|
using namespace boost::numeric;
|
|
safe<int> x, y;
|
|
is.seekg(0);
|
|
try{
|
|
is >> x >> y; // get integer values from the user
|
|
std::cout << x << ' ' << y << std::endl;
|
|
std::cout << "error NOT detected!" << std::endl;
|
|
}
|
|
catch(std::exception & e){
|
|
std::cout << e.what() << std::endl;
|
|
std::cout << "error detected!" << std::endl;
|
|
}
|
|
}
|
|
return 0;
|
|
}
|
|
</pre>
|
|
<p>Without
|
|
safe integer, one will have to insert new code every time an integer
|
|
variable is retrieved. This is a tedious and error prone procedure. Here
|
|
we have used program input. But in fact this problem can occur with any
|
|
externally produced input.</p>
|
|
</div>
|
|
<table xmlns:rev="http://www.cs.rpi.edu/~gregod/boost/tools/doc/revision" width="100%"><tr>
|
|
<td align="left"></td>
|
|
<td align="right"><div class="copyright-footer">Copyright © 2012 Robert Ramey<p><a href="http://www.boost.org/LICENSE_1_0.txt" target="_top">Subject to Boost
|
|
Software License</a></p>
|
|
</div></td>
|
|
</tr></table>
|
|
<hr>
|
|
<div class="spirit-nav">
|
|
<a accesskey="p" href="5.html"><img src="../images/prev.png" alt="Prev"></a><a accesskey="u" href="../tutorial.html"><img src="../images/up.png" alt="Up"></a><a accesskey="h" href="../index.html"><img src="../images/home.png" alt="Home"></a><a accesskey="n" href="7.html"><img src="../images/next.png" alt="Next"></a>
|
|
</div>
|
|
</body>
|
|
</html>
|