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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/define_preprocessor.html | |
Initial import (2.0.2-6)2.0.2-6
Diffstat (limited to 'reference/C/SYNTAX/define_preprocessor.html')
| -rw-r--r-- | reference/C/SYNTAX/define_preprocessor.html | 77 |
1 files changed, 77 insertions, 0 deletions
diff --git a/reference/C/SYNTAX/define_preprocessor.html b/reference/C/SYNTAX/define_preprocessor.html new file mode 100644 index 0000000..4023d2b --- /dev/null +++ b/reference/C/SYNTAX/define_preprocessor.html @@ -0,0 +1,77 @@ +<title>define preprocessor</title> +<head> +<script language="JavaScript"> +</script> +</head> +<body bgcolor="#ffffcc"> +<hr> +<center><h1>#define preprocessor</h1></center> +<hr> +<p> +The <b>#define</b> preprocessor allows us to define symbolic names and constants. +A quick example<p> +<pre> + #define PI 3.14159 +</pre> +This statement will translate every occurance of PI in the program to 3.14159. +Here is a more complete example:<p> +<pre> + + #define PI 3.14159 + main() + { + int r=10; + float cir; + cir = PI * (r*r); + } +</pre> +This feature is partically usefull for defining 'magic' numbers.<p> + +<hr> +<h2>See Also:</h2> +<ul> +<li>A related C keyword is <a href=enum.html>enum</a> which can be used to +build lists of aliases.<p> + +<li>Another related C keyword is <a href=const.html>const</a>. +<p> + +<li>An advanced use of #define is in the creation of <a href=macros.html> +macros</a>. +</ul> + +<hr> +<h2>Examples:</h2> +<a href="../EXAMPLES/define.c"><img src="../../GRAPHICS/computer.gif"></a> +example program.<p> + +<a href="../EXAMPLES/enum5.c"><img src="../../GRAPHICS/computer.gif"></a> +Conflict between enum and #define.<p> + +<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> |