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<title>PTypes: cset: constructors</title>
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<p><a href="../index.html"><img src="title-21.png" width="253" height="39" alt="C++ Portable Types Library (PTypes) Version 2.1" border="0"></a>
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<p class="hpath"><a href="index.html">Top</a>: <a href="basic.html">Basic types</a>:
<a href="cset.html">cset</a>: Constructors</p>
<blockquote>
<pre class="lang">#include <ptypes.h>
class cset {
cset();
cset(const cset& s);
cset(const char* setinit);
}
</pre>
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<p><span class="def">cset::cset()</span> -- default constructor, initializes
the set object to an empty set.</p>
<p><span class="def">cset::cset(const cset& s)</span> -- copy constructor.</p>
<p><span class="def">cset::cset(const char* setinit)</span> constructs a character
set from a string. The <span class="lang">setinit</span> parameter is a sequence
of characters, range specifiers and escape sequences. Range specifier consists
of: lower boundary, dash "-" and higher boundary, e.g. "A-Z".
Escape sequence begins with tilde "~" and can be followed by a two-digit
hexadecimal number. Escape sequences are also used to include special characters
tilde "~" and dash "-" (see examples below).</p>
<p>Constructing character sets using this interpreter can be a time-consuming
operation. A better practice is to declare all constant character sets as static
variables, so that the interpretation of all set constructing strings will be
done only once during program startup.</p>
<p>An initializer string can also be passed to a <span class="lang">cset</span>
object through <span class="lang">assign()</span>.</p>
<p><b>Note</b>: this constructor does not generate errors if the syntax is violated.</p>
<p><b>Examples:</b></p>
<blockquote>
<pre>cset s1 = "135A-CZ"; <span class="comment">// digits 1, 3, 5, letters A through C, and also Z</span>
cset wspace1 = "~09~0d~0a "; <span class="comment">// tab, CR, LF and space</span>
cset wspace2 = "~00-~20"; <span class="comment">// all control and whitespace chars</span>
cset s2 = ":@~~"; <span class="comment">// colon, at and tilde (must be escaped with another tilde)</span>
</pre>
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<p class="seealso">See also: <a href="cset.operators.html">Operators</a>, <a href="cset.manipulation.html">Manipulation</a></p>
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