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| author | Tobias Klauser <tklauser@distanz.ch> | 2008-01-27 11:37:44 +0100 |
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| committer | Tobias Klauser <tklauser@xenon.tklauser.home> | 2008-01-27 11:37:44 +0100 |
| commit | 7e0f021a9aec35fd8e6725e87e3313b101d26f5e (patch) | |
| tree | b1cacc4b24393f517aeb4610e9e1021f954307a8 /reference/C/SYNTAX/idioms.html | |
Initial import (2.0.2-6)2.0.2-6
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| -rw-r--r-- | reference/C/SYNTAX/idioms.html | 136 |
1 files changed, 136 insertions, 0 deletions
diff --git a/reference/C/SYNTAX/idioms.html b/reference/C/SYNTAX/idioms.html new file mode 100644 index 0000000..62247d3 --- /dev/null +++ b/reference/C/SYNTAX/idioms.html @@ -0,0 +1,136 @@ +<title>Idioms</title> +<head> +<script language="JavaScript"> +</script> +</head> +<body bgcolor="#ffffcc"> +<hr> +<center> +<h1>Idioms</h1> +</center> +<hr> +<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> +<p> +<center> +<table border=2 bgcolor=ivory> +<tr><td> +<pre> + + *ptr++ = '\0'; +</pre> +</td></tr> +</table> +</center> + +<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> +<p> +<center> +<table border=2 bgcolor=ivory> +<tr><td> +<pre> + + *++ptr = '\0'; +</pre> +</td></tr> +</table> +</center> + +<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. +<p> +<center> +<table border=2 bgcolor=ivory> +<tr><td> +<pre> + + main(a) {a="main(a) {a=%c%s%c;printf(a,34,a,34);}";printf(a,34,a,34);} +</pre> +</td></tr> +</table> +</center> + +<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. +<p> +<center> +<table border=2 bgcolor=ivory> +<tr><td> +<pre> + + one ^= two; + two ^= one; + one ^= two; +</pre> +</td></tr> +</table> +</center> + +<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> +<center> +<table border=2 bgcolor=ivory> +<tr><td> +<pre> + + printf("%s\n", Str ? Str : "Null"); +</pre> +</td></tr> +</table> +</center> + + + +<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> + +<hr> +<p> +<center> +<table border=2 width="80%" bgcolor="ivory"> +<tr align=center> +<td width="25%"> +<a href="../cref.html"> Top</a> +</td><td width="25%"> +<a href="../master_index.html"> Master Index</a> +</td><td width="25%"> +<a href="keywords.html"> Keywords</a> +</td><td width="25%"> +<a href="../FUNCTIONS/funcref.htm"> Functions</a> +</td> +</tr> +</table> +</center> +<p> +<hr> +<address>Martin Leslie +</address><p> +</body> +</html> |