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<title>Idioms</title>
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<h1>Idioms</h1>
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<p>
Here are some C idioms that may be usefull.
<p><hr align=center width="50%"><p>
Place <code>\0</code> at the location pointed to by <code>ptr</code>
then increment <code>ptr</code>
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<pre>
*ptr++ = '\0';
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<p><hr align=center width="50%"><p>
Increment <code>ptr</code> then
place <code>\0</code> at the location pointed to by <code>ptr</code>
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<pre>
*++ptr = '\0';
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<p><hr align=center width="50%"><p>
This program will print its self! I guess its not of any real
use, but I think its clever.
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<pre>
main(a) {a="main(a) {a=%c%s%c;printf(a,34,a,34);}";printf(a,34,a,34);}
</pre>
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<p><hr align=center width="50%"><p>
This is something I saw out on the web. It swaps the value of two
variables without
using a third variable as a temporary store.
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<pre>
one ^= two;
two ^= one;
one ^= two;
</pre>
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<a name=printf>
<p><hr align=center width="50%"><p>
Have you ever had a SEGV from <a href="../FUNCTIONS/printf.html">printf</a>
because you passed a NULL pointer to a %s flag???. This idiom will put
a stop to all that nonsence.
<p>
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<pre>
printf("%s\n", Str ? Str : "Null");
</pre>
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<p><hr align=center width="50%"><p>
<p>
<img src="../../GRAPHICS/computer.gif" alt="o">
<a href=../EXAMPLES/swap.c>Program swapping the contents of two variables</a>.
<p>
<hr>
<h2>See Also:</h2>
<img src="../../GRAPHICS/whiteball.gif" alt="o">
<a href="got_ya.html">Common Coding Errors</a>.<p>
<p>
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<p>
<hr>
<address>Martin Leslie
</address><p>
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