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<title>Using the GNU Compiler Collection (GCC)</title>
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Node:<a name="Min%20and%20Max">Min and Max</a>,
Next:<a rel="next" accesskey="n" href="Volatiles.html#Volatiles">Volatiles</a>,
Up:<a rel="up" accesskey="u" href="C---Extensions.html#C++%20Extensions">C++ Extensions</a>
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<h3 class="section">Minimum and Maximum Operators in C++</h3>
<p>It is very convenient to have operators which return the "minimum" or the
"maximum" of two arguments. In GNU C++ (but not in GNU C),
<dl>
<dt><code></code><var>a</var><code> <? </code><var>b</var><code></code>
<dd>is the <dfn>minimum</dfn>, returning the smaller of the numeric values
<var>a</var> and <var>b</var>;
<br><dt><code></code><var>a</var><code> >? </code><var>b</var><code></code>
<dd>is the <dfn>maximum</dfn>, returning the larger of the numeric values <var>a</var>
and <var>b</var>.
</dl>
<p>These operations are not primitive in ordinary C++, since you can
use a macro to return the minimum of two things in C++, as in the
following example.
<pre class="example"> #define MIN(X,Y) ((X) < (Y) ? : (X) : (Y))
</pre>
<p>You might then use <code>int min = MIN (i, j);</code> to set <var>min</var> to
the minimum value of variables <var>i</var> and <var>j</var>.
<p>However, side effects in <code>X</code> or <code>Y</code> may cause unintended
behavior. For example, <code>MIN (i++, j++)</code> will fail, incrementing
the smaller counter twice. The GNU C <code>typeof</code> extension allows you
to write safe macros that avoid this kind of problem (see <a href="Typeof.html#Typeof">Typeof</a>).
However, writing <code>MIN</code> and <code>MAX</code> as macros also forces you to
use function-call notation for a fundamental arithmetic operation.
Using GNU C++ extensions, you can write <code>int min = i <? j;</code>
instead.
<p>Since <code><?</code> and <code>>?</code> are built into the compiler, they properly
handle expressions with side-effects; <code>int min = i++ <? j++;</code>
works correctly.
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