source: public/doc/gnu-c/Constructing-Array-Values.html@ 02598c2

Last change on this file since 02598c2 was 02598c2, checked in by Mikhail Kirillov <w96k@…>, on Oct 6, 2022 at 12:36:29 PM

Add gnu-c
  • Property mode set to 100644
File size: 4.7 KB
Line 
1<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
2<html>
3<!-- Copyright (C) 2022 Richard Stallman and Free Software Foundation, Inc.
4
5(The work of Trevis Rothwell and Nelson Beebe has been assigned or
6licensed to the FSF.)
7
8Permission is granted to copy, distribute and/or modify this document
9under the terms of the GNU Free Documentation License, Version 1.3 or
10any later version published by the Free Software Foundation; with the
11Invariant Sections being "GNU General Public License," with the
12Front-Cover Texts being "A GNU Manual," and with the Back-Cover
13Texts as in (a) below. A copy of the license is included in the
14section entitled "GNU Free Documentation License."
15
16(a) The FSF's Back-Cover Text is: "You have the freedom to copy and
17modify this GNU manual. Buying copies from the FSF supports it in
18developing GNU and promoting software freedom." -->
19<!-- Created by GNU Texinfo 6.7, http://www.gnu.org/software/texinfo/ -->
20<head>
21<meta http-equiv="Content-Type" content="text/html; charset=utf-8">
22<title>Constructing Array Values (GNU C Language Manual)</title>
23
24<meta name="description" content="Constructing Array Values (GNU C Language Manual)">
25<meta name="keywords" content="Constructing Array Values (GNU C Language Manual)">
26<meta name="resource-type" content="document">
27<meta name="distribution" content="global">
28<meta name="Generator" content="makeinfo">
29<link href="index.html" rel="start" title="Top">
30<link href="Symbol-Index.html" rel="index" title="Symbol Index">
31<link href="index.html#SEC_Contents" rel="contents" title="Table of Contents">
32<link href="Arrays.html" rel="up" title="Arrays">
33<link href="Arrays-of-Variable-Length.html" rel="next" title="Arrays of Variable Length">
34<link href="Multidimensional-Arrays.html" rel="prev" title="Multidimensional Arrays">
35<style type="text/css">
36<!--
37a.summary-letter {text-decoration: none}
38blockquote.indentedblock {margin-right: 0em}
39div.display {margin-left: 3.2em}
40div.example {margin-left: 3.2em}
41div.lisp {margin-left: 3.2em}
42kbd {font-style: oblique}
43pre.display {font-family: inherit}
44pre.format {font-family: inherit}
45pre.menu-comment {font-family: serif}
46pre.menu-preformatted {font-family: serif}
47span.nolinebreak {white-space: nowrap}
48span.roman {font-family: initial; font-weight: normal}
49span.sansserif {font-family: sans-serif; font-weight: normal}
50ul.no-bullet {list-style: none}
51-->
52</style>
53
54
55</head>
56
57<body lang="en">
58<span id="Constructing-Array-Values"></span><div class="header">
59<p>
60Next: <a href="Arrays-of-Variable-Length.html" accesskey="n" rel="next">Arrays of Variable Length</a>, Previous: <a href="Multidimensional-Arrays.html" accesskey="p" rel="prev">Multidimensional Arrays</a>, Up: <a href="Arrays.html" accesskey="u" rel="up">Arrays</a> &nbsp; [<a href="index.html#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="Symbol-Index.html" title="Index" rel="index">Index</a>]</p>
61</div>
62<hr>
63<span id="Constructing-Array-Values-1"></span><h3 class="section">16.8 Constructing Array Values</h3>
64<span id="index-constructing-array-values"></span>
65<span id="index-array-values_002c-constructing"></span>
66
67<p>You can construct an array from elements by writing them inside
68braces, and preceding all that with the array type&rsquo;s designator in
69parentheses. There is no need to specify the array length, since the
70number of elements determines that. The constructor looks like this:
71</p>
72<div class="example">
73<pre class="example">(<var>elttype</var>[]) { <var>elements</var> };
74</pre></div>
75
76<p>Here is an example, which constructs an array of string pointers:
77</p>
78<div class="example">
79<pre class="example">(char *[]) { &quot;x&quot;, &quot;y&quot;, &quot;z&quot; };
80</pre></div>
81
82<p>That&rsquo;s equivalent in effect to declaring an array with the same
83initializer, like this:
84</p>
85<div class="example">
86<pre class="example">char *array[] = { &quot;x&quot;, &quot;y&quot;, &quot;z&quot; };
87</pre></div>
88
89<p>and then using the array.
90</p>
91<p>If all the elements are simple constant expressions, or made up of
92such, then the compound literal can be coerced to a pointer to its
93zeroth element and used to initialize a file-scope variable
94(see <a href="File_002dScope-Variables.html">File-Scope Variables</a>), as shown here:
95</p>
96<div class="example">
97<pre class="example">char **foo = (char *[]) { &quot;x&quot;, &quot;y&quot;, &quot;z&quot; };
98</pre></div>
99
100<p>The data type of <code>foo</code> is <code>char **</code>, which is a pointer
101type, not an array type. The declaration is equivalent to defining
102and then using an array-type variable:
103</p>
104<div class="example">
105<pre class="example">char *nameless_array[] = { &quot;x&quot;, &quot;y&quot;, &quot;z&quot; };
106char **foo = &amp;nameless_array[0];
107</pre></div>
108
109
110
111
112</body>
113</html>
Note: See TracBrowser for help on using the repository browser.