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<title>PTypes: cset: operators</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>: Operators</p>
<blockquote>
<pre class="lang">#include <ptypes.h>
class cset {
<span class="comment"> // assignment</span>
cset& operator =(const cset& s);
<span class="comment"> // union</span>
cset& operator +=(const cset& s);
cset& operator +=(char b);
cset operator +(const cset& s) const;
cset operator +(char b) const;
friend cset operator +(char b, const cset& s);
<span class="comment"> // difference</span>
cset& operator -=(const cset& s);
cset& operator -=(char b);
cset operator -(const cset& s) const;
cset operator -(char b) const;
<span class="comment"> // intersection</span>
cset& operator *=(const cset& s);
cset operator *(const cset& s) const;
<span class="comment"> // comparison</span>
bool operator ==(const cset& s) const;
bool operator !=(const cset& s) const;
bool operator <=(const cset& s) const;
bool operator >=(const cset& s) const;
<span class="comment"> // membership</span>
friend bool operator& (char b, const cset& s);
}
</pre>
</blockquote>
<p>The following rules apply to +, -, and *:</p>
<ul>
<li>
<p>An ordinal O is in X + Y if and only if O is in X or Y (or both). Equivalent
of bitwise <b>OR</b>.</p>
</li>
<li>
<p> O is in X - Y if and only if O is in X but not in Y. Equivalent of bitwise
<b>AND NOT</b>.</p>
</li>
<li>
<p>O is in X * Y if and only if O is in both X and Y. Equivalent of bitwise <b>AND</b>.</p>
</li>
</ul>
<p>The following rules apply to comparison operations <=, >=, ==, !=:</p>
<ul>
<li>
<p> X <= Y is true just in case every member of X is a member of Y; Z >= W is
equivalent to W <= Z.</p>
</li>
<li>
<p>U == V is true just in case U and V contain exactly the same members; otherwise,
U != V is true.</p>
</li>
</ul>
<p> For an ordinal O and a set S, O & S is true just in case O is a member
of S. Unlike the Pascal language, where membership operator is <b>in</b>, PTypes
uses ampersand "&" as a membership test operator.</p>
<p><b>Note</b>: regardless of whether default char is signed or unsigned (usually
set through compiler options) <span class="lang">cset</span> always treats char
arguments as unsigned. This means, if the value of an argument is -1, e.g. in
call to <span class="lang">operator &</span> or <span class="lang">operator
+</span>, the value will be converted to 255, -2 will be treated as 254, etc.</p>
<p class="seealso">See also: <a href="cset.constructors.html">Constructors</a>,
<a href="cset.manipulation.html">Manipulation</a></p>
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