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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/union.html | |
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diff --git a/reference/C/SYNTAX/union.html b/reference/C/SYNTAX/union.html new file mode 100644 index 0000000..5334e3b --- /dev/null +++ b/reference/C/SYNTAX/union.html @@ -0,0 +1,89 @@ +<title>The UNION keyword.</title> +<head> +<script language="JavaScript"> +</script> +</head> +<body bgcolor="#ffffcc"> +<hr> +<center><h1>The UNION keyword.</h1></center> +<hr> + +The <b>union</b> <a href="../glossary.html#keyword">keyword</a> allows several +variables of different type and size to occupy the same storage location. +<p> +The syntax to define a union is simular to the +<a href="struct.html">struct</a> keyword as shown below:<p> + + +<pre> + union union_def { int a; float b; char c;} ; +</pre> + +and a variable declared with either of these statements: + +<pre> + union union_def union_var; + union { int a; float b; char c;} union_var; +</pre> + +If you wish to initalise a variable you can say: + +<pre> + union { int a; float b; char c;} union_var=97; +</pre> + +By default the first variable (<b>a</b>) is initalised. +<p> + +To assign a value to a variable you can say: + +<pre> + union_var.b=99.99; + union_var.a=34; + union_var.c='x'; +</pre> +It's important to note that the storage will only hold ONE value, +looking at the +three lines above, <b>union_var.a</b> overwrites <b>union_var.b</b> and +then <b>union_var.c</b> overwrites <b>union_var.a</b><p> + + + +I have yet to see more than one use for this keyword. +<hr> +<h2>Examples:</h2> +<img src="../../GRAPHICS/computer.gif" align=left> +<a href="../EXAMPLES/union.c"> Here is an example.</a> +<br clear=left> +<hr> +<h2>See also:</h2> +<ul> +<li><a href="struct.html">struct</a> keyword. +</ul> + + +<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> |