-
Notifications
You must be signed in to change notification settings - Fork 1
Expand file tree
/
Copy pathdefaultfloat.html
More file actions
317 lines (257 loc) · 20.9 KB
/
defaultfloat.html
File metadata and controls
317 lines (257 loc) · 20.9 KB
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
<!doctype html>
<html class="cpprefjp" lang="ja" itemscope="" itemtype="http://schema.org/WebPage">
<head>
<!-- Google tag (gtag.js) -->
<script async src="https://www.googletagmanager.com/gtag/js?id=G-NXNBNVBTJS"></script>
<script>
window.dataLayer = window.dataLayer || [];
function gtag(){dataLayer.push(arguments);}
gtag('js', new Date());
gtag('config', 'G-NXNBNVBTJS');
</script>
<meta charset="UTF-8">
<title>defaultfloat - cpprefjp C++日本語リファレンス</title>
<meta name="viewport" content="width=device-width,initial-scale=1">
<meta name="keywords" content="
C++,標準ライブラリ,リファレンス,ドキュメント,STL,std,ios,std,function,cpp11
">
<meta name="title" content="defaultfloat - cpprefjp C++日本語リファレンス" />
<meta itemprop="name" content="defaultfloat - cpprefjp C++日本語リファレンス" />
<meta property="og:title" content="defaultfloat - cpprefjp C++日本語リファレンス" />
<meta property="og:url" content="https://cpprefjp.github.io/reference/ios/defaultfloat.html" />
<meta property="og:site_name" content="cpprefjp - C++日本語リファレンス" />
<meta property="og:type" content="article" />
<meta property="og:description" content="浮動小数点数を初期状態の書式で出力することを指示するマニピュレータ。" />
<meta name="twitter:card" content="summary" />
<meta name="twitter:title" content="defaultfloat - cpprefjp C++日本語リファレンス" />
<meta name="twitter:url" content="https://cpprefjp.github.io/reference/ios/defaultfloat.html" />
<meta name="twitter:description" content="浮動小数点数を初期状態の書式で出力することを指示するマニピュレータ。" />
<link rel="alternate" type="application/atom+xml" title="Atom" href="https://cpprefjp.github.io/rss.xml" />
<link rel="apple-touch-icon" sizes="180x180" href="../../static/favicons/apple-touch-icon.png?cachebust=be86fa2321ebe02b6955b61b98b778e377bcbf95">
<link rel="icon" type="image/png" sizes="32x32" href="../../static/favicons/favicon-32x32.png?cachebust=be86fa2321ebe02b6955b61b98b778e377bcbf95">
<link rel="icon" type="image/png" sizes="16x16" href="../../static/favicons/favicon-16x16.png?cachebust=be86fa2321ebe02b6955b61b98b778e377bcbf95">
<link rel="manifest" href="../../manifest.json?cachebust=be86fa2321ebe02b6955b61b98b778e377bcbf95">
<meta name="theme-color" content="#f5f8fc">
<link rel="stylesheet" href="../../static/pygments/default.css?cachebust=be86fa2321ebe02b6955b61b98b778e377bcbf95">
<!-- <link rel="stylesheet" href="../../static/css/root.css"> -->
<link href="../../static/kunai/css/kunai-stage-0.css?cachebust=be86fa2321ebe02b6955b61b98b778e377bcbf95" rel="stylesheet">
<link href="../../static/kunai/css/kunai-stage-1.css?cachebust=be86fa2321ebe02b6955b61b98b778e377bcbf95" rel="stylesheet">
<link href="../../static/kunai/css/kunai-stage-2.css?cachebust=be86fa2321ebe02b6955b61b98b778e377bcbf95" rel="stylesheet">
<link href="../../static/kunai/css/kunai-stage-3.css?cachebust=be86fa2321ebe02b6955b61b98b778e377bcbf95" rel="stylesheet">
<script type="text/javascript" src="../../static/kunai/js/kunai-vendor.js?cachebust=be86fa2321ebe02b6955b61b98b778e377bcbf95"></script>
<script type="text/javascript" src="../../static/kunai/js/kunai.js?cachebust=be86fa2321ebe02b6955b61b98b778e377bcbf95"></script>
<script type="text/javascript">
document.addEventListener('DOMContentLoaded', function() {
var kn = new Kunai;
kn.cpprefjp();
});
</script>
</head>
<body>
<header data-kunai-mdinfo="{"meta": {"header": ["ios"], "namespace": ["std"], "id-type": ["function"], "cpp": ["cpp11"]}, "sources": [{"id": "f3fb1b36bd66193903f5ab0ca73ba284e4855a1f", "source": "#include <iostream>\n#include <iomanip>\n\nint main()\n{\n std::cout << std::right;\n std::cout << std::setw(12) << \"defaultfloat\" << ' ';\n std::cout << std::setw(17) << \"fixed\" << ' ';\n std::cout << std::setw(15) << \"scientific\" << ' ';\n std::cout << std::setw(15) << \"hexfloat\" << std::endl;\n for (double i = 1e-6; i < 1e10; i *= 20) {\n std::cout << std::setw(12) << std::defaultfloat << i << ' ';\n std::cout << std::setw(17) << std::fixed << i << ' ';\n std::cout << std::setw(15) << std::scientific << i << ' ';\n std::cout << std::setw(15) << std::hexfloat << i << std::endl;\n }\n}\n"}], "page_id": ["reference", "ios", "defaultfloat"]}">
<nav class="navbar navbar-default" role="navigation">
<div class="container-fluid">
<div class="navbar-header">
<button type="button" class="navbar-toggle collapsed" data-toggle="collapse" data-target="#navbar-collapse">
<span class="sr-only">Toggle navigation</span>
<span class="icon-bar"></span>
<span class="icon-bar"></span>
<span class="icon-bar"></span>
</button>
<a class="navbar-brand" href="../../index.html">
<div class="title-wrapper clearfix">
<div class="title">cpprefjp - C++日本語リファレンス</div>
</div>
</a>
</div>
<div class="collapse navbar-collapse" id="navbar-collapse">
<ul class="nav navbar-nav navbar-right">
<li>
<div class="google-search">
<script>
(function() {
var cx = '013316413321391058734:ji_u66hl7hq';
var gcse = document.createElement('script');
gcse.type = 'text/javascript';
gcse.async = true;
gcse.src = (document.location.protocol == 'https:' ? 'https:' : 'http:') +
'//www.google.com/cse/cse.js?cx=' + cx;
var s = document.getElementsByTagName('script')[0];
s.parentNode.insertBefore(gcse, s);
})();
</script>
<div class="gcse-search"></div>
</div>
</li>
<li>
<a href="https://github.com/cpprefjp/site">GitHub Project</a>
</li>
</ul>
</div>
</div>
</nav>
</header>
<main id="main" role="main">
<div class="container-fluid">
<div class="row">
<div class="col-sm-9 col-sm-push-3" itemscope itemtype="http://schema.org/Article">
<div class="row">
<div class="col-sm-12 google-search-result">
<gcse:searchresults></gcse:searchresults>
</div>
</div>
<div class="row">
<div class="col-sm-12 content-header">
<ol class="breadcrumb">
<li itemscope itemtype="http://www.schema.org/SiteNavigationElement">
<span>
<a href="../../index.html" itemprop="url">
<i class="fa fa-fw fa-home"></i>
</a>
</span>
</li>
<li itemscope itemtype="http://www.schema.org/SiteNavigationElement">
<span>
<a href="../../reference.html" itemprop="url">
<span itemprop="name">リファレンス</span>
</a>
</span>
</li>
<li itemscope itemtype="http://www.schema.org/SiteNavigationElement">
<span>
<a href="../../reference/ios.html" itemprop="url">
<span itemprop="name">ios</span>
</a>
</span>
</li>
<li class="active" itemscope itemtype="http://www.schema.org/SiteNavigationElement">
<span>
<span itemprop="name">defaultfloat</span>
</span>
</li>
</ol>
<div class="crsearch"></div>
</div>
</div>
<div class="row">
<div class="col-sm-12 edit-button">
<p class="text-right"><small>
最終更新日時(UTC):
<span itemprop="datePublished" content="2024-06-11T13:45:38">
2024年06月11日 13時45分38秒
</span>
<br/>
<span itemprop="author" itemscope itemtype="http://schema.org/Person">
<span itemprop="name">Akira Takahashi</span>
</span>
が更新
</small></p>
<p class="text-right">
<a class="history" target="_blank" href="https://github.com/cpprefjp/site/commits/master/reference/ios/defaultfloat.md">
<span class="fa fa-fw fa-clock-o fa-flip-horizontal"></span>履歴
</a>
<a class="edit" target="_blank" href="https://github.com/cpprefjp/site/edit/master/reference/ios/defaultfloat.md">
<span class="fa fa-fw fa-pencil"></span>編集
</a>
</p>
</div>
</div>
<div class="row">
<div class="col-sm-12 content-body">
<div class="identifier-type">function</div><div class="header"><ios></div><h1 itemprop="name"><span class="namespace" title="namespace std">std::</span><span class="token">defaultfloat</span><span class="cpp cpp11" title="C++11で追加">(C++11)</span></h1>
<div itemprop="articleBody"><p><div class="codehilite"><pre><span></span><code><span class="k">namespace</span><span class="w"> </span><span class="nn">std</span><span class="w"> </span><span class="p">{</span>
<span class="w"> </span><span class="n">ios_base</span><span class="o">&</span><span class="w"> </span><span class="nf">defaultfloat</span><span class="p">(</span><span class="n">ios_base</span><span class="o">&</span><span class="w"> </span><span class="n">str</span><span class="p">);</span>
<span class="p">}</span>
</code></pre></div>
</p>
<h2>概要</h2>
<p>浮動小数点数を初期状態の書式で出力することを指示するマニピュレータ。</p>
<p>この書式は、出力値や出力すべき精度により小数点数表記と指数表記が切り替わるものである（<code><a href="https://web.archive.org/web/20230605132525/https://linuxjm.osdn.jp/html/LDP_man-pages/man3/printf.3.html" target="_blank">printf()</a></code>関数の<code>%g</code>／<code>%G</code>相当）。</p>
<h2>効果</h2>
<p><code>str.unsetf(ios_base::floatfield)</code>を実行する。</p>
<h2><a class="cpprefjp-defined-word" data-desc="関数呼び出し式の評価結果となるオブジェクト・値">戻り値</a></h2>
<p>実引数の<code>str</code>オブジェクト。</p>
<h2>例</h2>
<p><div class="yata" id="f3fb1b36bd66193903f5ab0ca73ba284e4855a1f"><div class="codehilite"><pre><span></span><code><span class="cp">#include <a href="../iostream.html"><iostream></a></span>
<span class="cp">#include <a href="../iomanip.html"><iomanip></a></span>
<span class="kt">int</span><span class="w"> </span><span class="nf">main</span><span class="p">()</span>
<span class="p">{</span>
<span class="w"> </span><span class="n"><a href="../iostream/cout.html">std::cout</a></span><span class="w"> </span><span class="o"><<</span><span class="w"> </span><span class="n"><a href="right.html">std::right</a></span><span class="p">;</span>
<span class="w"> </span><span class="n"><a href="../iostream/cout.html">std::cout</a></span><span class="w"> </span><span class="o"><<</span><span class="w"> </span><span class="n"><a href="../iomanip/setw.html">std::setw</a></span><span class="p">(</span><span class="mi">12</span><span class="p">)</span><span class="w"> </span><span class="o"><<</span><span class="w"> </span><span class="s">"defaultfloat"</span><span class="w"> </span><span class="o"><<</span><span class="w"> </span><span class="sc">' '</span><span class="p">;</span>
<span class="w"> </span><span class="n"><a href="../iostream/cout.html">std::cout</a></span><span class="w"> </span><span class="o"><<</span><span class="w"> </span><span class="n"><a href="../iomanip/setw.html">std::setw</a></span><span class="p">(</span><span class="mi">17</span><span class="p">)</span><span class="w"> </span><span class="o"><<</span><span class="w"> </span><span class="s">"fixed"</span><span class="w"> </span><span class="o"><<</span><span class="w"> </span><span class="sc">' '</span><span class="p">;</span>
<span class="w"> </span><span class="n"><a href="../iostream/cout.html">std::cout</a></span><span class="w"> </span><span class="o"><<</span><span class="w"> </span><span class="n"><a href="../iomanip/setw.html">std::setw</a></span><span class="p">(</span><span class="mi">15</span><span class="p">)</span><span class="w"> </span><span class="o"><<</span><span class="w"> </span><span class="s">"scientific"</span><span class="w"> </span><span class="o"><<</span><span class="w"> </span><span class="sc">' '</span><span class="p">;</span>
<span class="w"> </span><span class="n"><a href="../iostream/cout.html">std::cout</a></span><span class="w"> </span><span class="o"><<</span><span class="w"> </span><span class="n"><a href="../iomanip/setw.html">std::setw</a></span><span class="p">(</span><span class="mi">15</span><span class="p">)</span><span class="w"> </span><span class="o"><<</span><span class="w"> </span><span class="s">"hexfloat"</span><span class="w"> </span><span class="o"><<</span><span class="w"> </span><span class="n"><a href="../ostream/endl.html">std::endl</a></span><span class="p">;</span>
<span class="w"> </span><span class="k">for</span><span class="w"> </span><span class="p">(</span><span class="kt">double</span><span class="w"> </span><span class="n">i</span><span class="w"> </span><span class="o">=</span><span class="w"> </span><span class="mf">1e-6</span><span class="p">;</span><span class="w"> </span><span class="n">i</span><span class="w"> </span><span class="o"><</span><span class="w"> </span><span class="mf">1e10</span><span class="p">;</span><span class="w"> </span><span class="n">i</span><span class="w"> </span><span class="o">*=</span><span class="w"> </span><span class="mi">20</span><span class="p">)</span><span class="w"> </span><span class="p">{</span>
<span class="w"> </span><span class="n"><a href="../iostream/cout.html">std::cout</a></span><span class="w"> </span><span class="o"><<</span><span class="w"> </span><span class="n"><a href="../iomanip/setw.html">std::setw</a></span><span class="p">(</span><span class="mi">12</span><span class="p">)</span><span class="w"> </span><span class="o"><<</span><span class="w"> </span><span class="n"><span style="color:#ff00000">std::defaultfloat</span></span><span class="w"> </span><span class="o"><<</span><span class="w"> </span><span class="n">i</span><span class="w"> </span><span class="o"><<</span><span class="w"> </span><span class="sc">' '</span><span class="p">;</span>
<span class="w"> </span><span class="n"><a href="../iostream/cout.html">std::cout</a></span><span class="w"> </span><span class="o"><<</span><span class="w"> </span><span class="n"><a href="../iomanip/setw.html">std::setw</a></span><span class="p">(</span><span class="mi">17</span><span class="p">)</span><span class="w"> </span><span class="o"><<</span><span class="w"> </span><span class="n"><a href="fixed.html">std::fixed</a></span><span class="w"> </span><span class="o"><<</span><span class="w"> </span><span class="n">i</span><span class="w"> </span><span class="o"><<</span><span class="w"> </span><span class="sc">' '</span><span class="p">;</span>
<span class="w"> </span><span class="n"><a href="../iostream/cout.html">std::cout</a></span><span class="w"> </span><span class="o"><<</span><span class="w"> </span><span class="n"><a href="../iomanip/setw.html">std::setw</a></span><span class="p">(</span><span class="mi">15</span><span class="p">)</span><span class="w"> </span><span class="o"><<</span><span class="w"> </span><span class="n"><a href="scientific.html">std::scientific</a></span><span class="w"> </span><span class="o"><<</span><span class="w"> </span><span class="n">i</span><span class="w"> </span><span class="o"><<</span><span class="w"> </span><span class="sc">' '</span><span class="p">;</span>
<span class="w"> </span><span class="n"><a href="../iostream/cout.html">std::cout</a></span><span class="w"> </span><span class="o"><<</span><span class="w"> </span><span class="n"><a href="../iomanip/setw.html">std::setw</a></span><span class="p">(</span><span class="mi">15</span><span class="p">)</span><span class="w"> </span><span class="o"><<</span><span class="w"> </span><span class="n"><a href="hexfloat.html">std::hexfloat</a></span><span class="w"> </span><span class="o"><<</span><span class="w"> </span><span class="n">i</span><span class="w"> </span><span class="o"><<</span><span class="w"> </span><span class="n"><a href="../ostream/endl.html">std::endl</a></span><span class="p">;</span>
<span class="w"> </span><span class="p">}</span>
<span class="p">}</span>
</code></pre></div>
</div></p>
<h3>出力</h3>
<p><pre><code>defaultfloat fixed scientific hexfloat
1e-006 0.000001 1.000000e-006 0x1.0c6f7ap-20
2e-005 0.000020 2.000000e-005 0x1.4f8b58p-16
0.0004 0.000400 4.000000e-004 0x1.a36e2fp-12
0.008 0.008000 8.000000e-003 0x1.0624ddp-7
0.16 0.160000 1.600000e-001 0x1.47ae14p-3
3.2 3.200000 3.200000e+000 0x1.99999ap+1
64 64.000000 6.400000e+001 0x1.000000p+6
1280 1280.000000 1.280000e+003 0x1.400000p+10
25600 25600.000000 2.560000e+004 0x1.900000p+14
512000 512000.000000 5.120000e+005 0x1.f40000p+18
1.024e+007 10240000.000000 1.024000e+007 0x1.388000p+23
2.048e+008 204800000.000000 2.048000e+008 0x1.86a000p+27
4.096e+009 4096000000.000000 4.096000e+009 0x1.e84800p+31
</code></pre></p>
<h2>実装例</h2>
<p>この実装はC++03の下でも可能である。</p>
<p><div class="codehilite"><pre><span></span><code><span class="k">namespace</span><span class="w"> </span><span class="nn">std</span><span class="w"> </span><span class="p">{</span>
<span class="w"> </span><span class="n">ios_base</span><span class="o">&</span><span class="w"> </span><span class="nf">defaultfloat</span><span class="p">(</span><span class="n">ios_base</span><span class="o">&</span><span class="w"> </span><span class="n">str</span><span class="p">)</span><span class="w"> </span><span class="p">{</span>
<span class="w"> </span><span class="n">str</span><span class="p">.</span><span class="n">unsetf</span><span class="p">(</span><span class="n">ios_base</span><span class="o">::</span><span class="n">floatfield</span><span class="p">);</span>
<span class="w"> </span><span class="k">return</span><span class="w"> </span><span class="n">str</span><span class="p">;</span>
<span class="w"> </span><span class="p">}</span>
<span class="p">}</span>
</code></pre></div>
</p>
<h2>バージョン</h2>
<h3>言語</h3>
<ul>
<li>C++11</li>
</ul>
<h3>処理系</h3>
<ul>
<li><a href="../../implementation.html#clang">Clang</a>: 3.0 <span aria-label="検証済" role="img" title="検証済">✅</span>, 3.1 <span aria-label="検証済" role="img" title="検証済">✅</span>, 3.2 <span aria-label="検証済" role="img" title="検証済">✅</span>, 3.3 <span aria-label="検証済" role="img" title="検証済">✅</span>, 3.4 <span aria-label="検証済" role="img" title="検証済">✅</span></li>
<li><a href="../../implementation.html#gcc">GCC</a>: 5.0 <span aria-label="検証済" role="img" title="検証済">✅</span></li>
<li><a href="../../implementation.html#icc">ICC</a>: ??</li>
<li><a href="../../implementation.html#visual_cpp">Visual C++</a>: 2010 <span aria-label="検証済" role="img" title="検証済">✅</span>, 2012 <span aria-label="検証済" role="img" title="検証済">✅</span></li>
</ul>
<h2>参照</h2>
<ul>
<li><code><a href="fixed.html">fixed</a></code></li>
<li><code><a href="scientific.html">scientific</a></code></li>
<li><code><a href="hexfloat.html">hexfloat</a></code></li>
<li><a href="http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2005/n1842.pdf" target="_blank">N1842 A Proposal to add two iostream manipulators to the C++ Standard Library</a></li>
<li><a href="http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2006/n1991.htm" target="_blank">N1991 Proposed Text for defaultfloat (N1842)</a></li>
</ul></div>
</div>
</div>
</div>
<div id="sidebar" class="col-sm-3 col-sm-pull-9">
</div>
</div>
</div>
</main>
<footer class="footer navbar navbar-default">
<div class="container-fluid">
<p><small>
本サイトの情報は、
<a href="https://creativecommons.org/licenses/by/4.0/deed.ja" rel="nofollow">クリエイティブ・コモンズ 表示 4.0 非移植 ライセンス(CC BY)</a>
の下に提供されています。
</small></p>
</div>
</footer>
</body>
</html>