backup/C-Plus-Plus
1
0
Fork 0
mirror of https://github.com/TheAlgorithms/C-Plus-Plus.git synced 2026-03-22 04:42:10 +08:00
Code Issues Projects Releases Wiki Activity
Files
495131a6791caea7f1cd8b78a45cf802b469ea62
C-Plus-Plus/d7/d89/double__factorial_8cpp.html
github-actions 08e8eb037e Documentation for 341ed50da8
2021-09-03 19:56:17 +00:00

314 lines
21 KiB
HTML
Raw Blame History

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "https://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<meta http-equiv="Content-Type" content="text/xhtml;charset=UTF-8"/>
<meta http-equiv="X-UA-Compatible" content="IE=11"/>
<meta name="generator" content="Doxygen 1.9.2"/>
<meta name="viewport" content="width=device-width, initial-scale=1"/>
<title>Algorithms_in_C++: math/double_factorial.cpp File Reference</title>
<link href="../../tabs.css" rel="stylesheet" type="text/css"/>
<script type="text/javascript" src="../../jquery.js"></script>
<script type="text/javascript" src="../../dynsections.js"></script>
<link href="../../navtree.css" rel="stylesheet" type="text/css"/>
<script type="text/javascript" src="../../resize.js"></script>
<script type="text/javascript" src="../../navtreedata.js"></script>
<script type="text/javascript" src="../../navtree.js"></script>
<link href="../../search/search.css" rel="stylesheet" type="text/css"/>
<script type="text/javascript" src="../../search/searchdata.js"></script>
<script type="text/javascript" src="../../search/search.js"></script>
<script type="text/x-mathjax-config">
MathJax.Hub.Config({
extensions: ["tex2jax.js", "TeX/AMSmath.js", "TeX/AMSsymbols.js"],
jax: ["input/TeX","output/HTML-CSS"],
});
</script>
<script type="text/javascript" async="async" src="https://cdnjs.cloudflare.com/ajax/libs/mathjax/2.7.7/MathJax.js?config=TeX-MML-AM_CHTML/MathJax.js"></script>
<link href="../../doxygen.css" rel="stylesheet" type="text/css" />
</head>
<body>
<div id="top"><!-- do not remove this div, it is closed by doxygen! -->
<div id="titlearea">
<table cellspacing="0" cellpadding="0">
<tbody>
<tr style="height: 56px;">
<td id="projectalign" style="padding-left: 0.5em;">
<div id="projectname">Algorithms_in_C++<span id="projectnumber">&#160;1.0.0</span>
</div>
<div id="projectbrief">Set of algorithms implemented in C++.</div>
</td>
</tr>
</tbody>
</table>
</div>
<!-- end header part -->
<!-- Generated by Doxygen 1.9.2 -->
<script type="text/javascript">
/* @license magnet:?xt=urn:btih:d3d9a9a6595521f9666a5e94cc830dab83b65699&amp;dn=expat.txt MIT */
var searchBox = new SearchBox("searchBox", "../../search",'Search','.html');
/* @license-end */
</script>
<script type="text/javascript" src="../../menudata.js"></script>
<script type="text/javascript" src="../../menu.js"></script>
<script type="text/javascript">
/* @license magnet:?xt=urn:btih:d3d9a9a6595521f9666a5e94cc830dab83b65699&amp;dn=expat.txt MIT */
$(function() {
initMenu('../../',true,false,'search.php','Search');
$(document).ready(function() { init_search(); });
});
/* @license-end */
</script>
<div id="main-nav"></div>
</div><!-- top -->
<div id="side-nav" class="ui-resizable side-nav-resizable">
<div id="nav-tree">
<div id="nav-tree-contents">
<div id="nav-sync" class="sync"></div>
</div>
</div>
<div id="splitbar" style="-moz-user-select:none;"
class="ui-resizable-handle">
</div>
</div>
<script type="text/javascript">
/* @license magnet:?xt=urn:btih:d3d9a9a6595521f9666a5e94cc830dab83b65699&amp;dn=expat.txt MIT */
$(document).ready(function(){initNavTree('d7/d89/double__factorial_8cpp.html','../../'); initResizable(); });
/* @license-end */
</script>
<div id="doc-content">
<!-- window showing the filter options -->
<div id="MSearchSelectWindow"
onmouseover="return searchBox.OnSearchSelectShow()"
onmouseout="return searchBox.OnSearchSelectHide()"
onkeydown="return searchBox.OnSearchSelectKey(event)">
</div>
<!-- iframe showing the search results (closed by default) -->
<div id="MSearchResultsWindow">
<iframe src="javascript:void(0)" frameborder="0"
name="MSearchResults" id="MSearchResults">
</iframe>
</div>
<div class="header">
<div class="summary">
<a href="#func-members">Functions</a> </div>
<div class="headertitle"><div class="title">double_factorial.cpp File Reference</div></div>
</div><!--header-->
<div class="contents">
<p>Compute <a href="https://en.wikipedia.org/wiki/Double_factorial" target="_blank">double factorial</a>: \(n!!\).
<a href="#details">More...</a></p>
<div class="textblock"><code>#include &lt;cassert&gt;</code><br />
<code>#include &lt;iostream&gt;</code><br />
</div><div class="textblock"><div class="dynheader">
Include dependency graph for double_factorial.cpp:</div>
<div class="dyncontent">
<div class="center"><iframe scrolling="no" frameborder="0" src="../../dd/d0e/double__factorial_8cpp__incl.svg" width="186" height="112"><p><b>This browser is not able to show SVG: try Firefox, Chrome, Safari, or Opera instead.</b></p></iframe>
</div>
</div>
</div><table class="memberdecls">
<tr class="heading"><td colspan="2"><h2 class="groupheader"><a id="func-members" name="func-members"></a>
Functions</h2></td></tr>
<tr class="memitem:a0a3c417360400093891a9ccddaa4be26"><td class="memItemLeft" align="right" valign="top">uint64_t&#160;</td><td class="memItemRight" valign="bottom"><a class="el" href="../../d7/d89/double__factorial_8cpp.html#a0a3c417360400093891a9ccddaa4be26">double_factorial_iterative</a> (uint64_t n)</td></tr>
<tr class="separator:a0a3c417360400093891a9ccddaa4be26"><td class="memSeparator" colspan="2">&#160;</td></tr>
<tr class="memitem:a68ba20fed2ce427f6469c7689437829d"><td class="memItemLeft" align="right" valign="top">uint64_t&#160;</td><td class="memItemRight" valign="bottom"><a class="el" href="../../d7/d89/double__factorial_8cpp.html#a68ba20fed2ce427f6469c7689437829d">double_factorial_recursive</a> (uint64_t n)</td></tr>
<tr class="separator:a68ba20fed2ce427f6469c7689437829d"><td class="memSeparator" colspan="2">&#160;</td></tr>
<tr class="memitem:abbbcebf3a2d0c67f4c3cfb5511a97981"><td class="memItemLeft" align="right" valign="top">void&#160;</td><td class="memItemRight" valign="bottom"><a class="el" href="../../d7/d89/double__factorial_8cpp.html#abbbcebf3a2d0c67f4c3cfb5511a97981">test</a> (uint64_t n, uint64_t expected)</td></tr>
<tr class="separator:abbbcebf3a2d0c67f4c3cfb5511a97981"><td class="memSeparator" colspan="2">&#160;</td></tr>
<tr class="memitem:a88ec9ad42717780d6caaff9d3d6977f9"><td class="memItemLeft" align="right" valign="top">void&#160;</td><td class="memItemRight" valign="bottom"><a class="el" href="../../d7/d89/double__factorial_8cpp.html#a88ec9ad42717780d6caaff9d3d6977f9">tests</a> ()</td></tr>
<tr class="separator:a88ec9ad42717780d6caaff9d3d6977f9"><td class="memSeparator" colspan="2">&#160;</td></tr>
<tr class="memitem:ae66f6b31b5ad750f1fe042a706a4e3d4"><td class="memItemLeft" align="right" valign="top">int&#160;</td><td class="memItemRight" valign="bottom"><a class="el" href="../../d7/d89/double__factorial_8cpp.html#ae66f6b31b5ad750f1fe042a706a4e3d4">main</a> ()</td></tr>
<tr class="separator:ae66f6b31b5ad750f1fe042a706a4e3d4"><td class="memSeparator" colspan="2">&#160;</td></tr>
</table>
<a name="details" id="details"></a><h2 class="groupheader">Detailed Description</h2>
<div class="textblock"><p >Compute <a href="https://en.wikipedia.org/wiki/Double_factorial" target="_blank">double factorial</a>: \(n!!\). </p>
<p >Double factorial of a non-negative integer <code>n</code>, is defined as the product of all the integers from 1 to n that have the same parity (odd or even) as n. <br />
It is also called as semifactorial of a number and is denoted by \(n!!\) </p>
</div><h2 class="groupheader">Function Documentation</h2>
<a id="a0a3c417360400093891a9ccddaa4be26" name="a0a3c417360400093891a9ccddaa4be26"></a>
<h2 class="memtitle"><span class="permalink"><a href="#a0a3c417360400093891a9ccddaa4be26">&#9670;&nbsp;</a></span>double_factorial_iterative()</h2>
<div class="memitem">
<div class="memproto">
<table class="memname">
<tr>
<td class="memname">uint64_t double_factorial_iterative </td>
<td>(</td>
<td class="paramtype">uint64_t&#160;</td>
<td class="paramname"><em>n</em></td><td>)</td>
<td></td>
</tr>
</table>
</div><div class="memdoc">
<p >Compute double factorial using iterative method </p>
<div class="fragment"><div class="line"><a id="l00017" name="l00017"></a><span class="lineno"> 17</span> {</div>
<div class="line"><a id="l00018" name="l00018"></a><span class="lineno"> 18</span> uint64_t res = 1;</div>
<div class="line"><a id="l00019" name="l00019"></a><span class="lineno"> 19</span> <span class="keywordflow">for</span> (uint64_t i = n;; i -= 2) {</div>
<div class="line"><a id="l00020" name="l00020"></a><span class="lineno"> 20</span> <span class="keywordflow">if</span> (i == 0 || i == 1)</div>
<div class="line"><a id="l00021" name="l00021"></a><span class="lineno"> 21</span> <span class="keywordflow">return</span> res;</div>
<div class="line"><a id="l00022" name="l00022"></a><span class="lineno"> 22</span> res *= i;</div>
<div class="line"><a id="l00023" name="l00023"></a><span class="lineno"> 23</span> }</div>
<div class="line"><a id="l00024" name="l00024"></a><span class="lineno"> 24</span> <span class="keywordflow">return</span> res;</div>
<div class="line"><a id="l00025" name="l00025"></a><span class="lineno"> 25</span>}</div>
</div><!-- fragment -->
</div>
</div>
<a id="a68ba20fed2ce427f6469c7689437829d" name="a68ba20fed2ce427f6469c7689437829d"></a>
<h2 class="memtitle"><span class="permalink"><a href="#a68ba20fed2ce427f6469c7689437829d">&#9670;&nbsp;</a></span>double_factorial_recursive()</h2>
<div class="memitem">
<div class="memproto">
<table class="memname">
<tr>
<td class="memname">uint64_t double_factorial_recursive </td>
<td>(</td>
<td class="paramtype">uint64_t&#160;</td>
<td class="paramname"><em>n</em></td><td>)</td>
<td></td>
</tr>
</table>
</div><div class="memdoc">
<p >Compute double factorial using resursive method. <br />
Recursion can be costly for large numbers. </p>
<div class="fragment"><div class="line"><a id="l00030" name="l00030"></a><span class="lineno"> 30</span> {</div>
<div class="line"><a id="l00031" name="l00031"></a><span class="lineno"> 31</span> <span class="keywordflow">if</span> (n &lt;= 1)</div>
<div class="line"><a id="l00032" name="l00032"></a><span class="lineno"> 32</span> <span class="keywordflow">return</span> 1;</div>
<div class="line"><a id="l00033" name="l00033"></a><span class="lineno"> 33</span> <span class="keywordflow">return</span> n * <a class="code hl_function" href="../../d7/d89/double__factorial_8cpp.html#a68ba20fed2ce427f6469c7689437829d">double_factorial_recursive</a>(n - 2);</div>
<div class="line"><a id="l00034" name="l00034"></a><span class="lineno"> 34</span>}</div>
<div class="ttc" id="adouble__factorial_8cpp_html_a68ba20fed2ce427f6469c7689437829d"><div class="ttname"><a href="../../d7/d89/double__factorial_8cpp.html#a68ba20fed2ce427f6469c7689437829d">double_factorial_recursive</a></div><div class="ttdeci">uint64_t double_factorial_recursive(uint64_t n)</div><div class="ttdef"><b>Definition:</b> double_factorial.cpp:30</div></div>
</div><!-- fragment --><div class="dynheader">
Here is the call graph for this function:</div>
<div class="dyncontent">
<div class="center"><iframe scrolling="no" frameborder="0" src="../../d7/d89/double__factorial_8cpp_a68ba20fed2ce427f6469c7689437829d_cgraph.svg" width="188" height="62"><p><b>This browser is not able to show SVG: try Firefox, Chrome, Safari, or Opera instead.</b></p></iframe>
</div>
</div>
</div>
</div>
<a id="ae66f6b31b5ad750f1fe042a706a4e3d4" name="ae66f6b31b5ad750f1fe042a706a4e3d4"></a>
<h2 class="memtitle"><span class="permalink"><a href="#ae66f6b31b5ad750f1fe042a706a4e3d4">&#9670;&nbsp;</a></span>main()</h2>
<div class="memitem">
<div class="memproto">
<table class="memname">
<tr>
<td class="memname">int main </td>
<td>(</td>
<td class="paramtype">void&#160;</td>
<td class="paramname"></td><td>)</td>
<td></td>
</tr>
</table>
</div><div class="memdoc">
<p >Main function </p>
<div class="fragment"><div class="line"><a id="l00067" name="l00067"></a><span class="lineno"> 67</span> {</div>
<div class="line"><a id="l00068" name="l00068"></a><span class="lineno"> 68</span> <a class="code hl_function" href="../../d7/d89/double__factorial_8cpp.html#a88ec9ad42717780d6caaff9d3d6977f9">tests</a>();</div>
<div class="line"><a id="l00069" name="l00069"></a><span class="lineno"> 69</span> <span class="keywordflow">return</span> 0;</div>
<div class="line"><a id="l00070" name="l00070"></a><span class="lineno"> 70</span>}</div>
<div class="ttc" id="adouble__factorial_8cpp_html_a88ec9ad42717780d6caaff9d3d6977f9"><div class="ttname"><a href="../../d7/d89/double__factorial_8cpp.html#a88ec9ad42717780d6caaff9d3d6977f9">tests</a></div><div class="ttdeci">void tests()</div><div class="ttdef"><b>Definition:</b> double_factorial.cpp:50</div></div>
</div><!-- fragment --><div class="dynheader">
Here is the call graph for this function:</div>
<div class="dyncontent">
<div class="center"><iframe scrolling="no" frameborder="0" src="../../d7/d89/double__factorial_8cpp_ae66f6b31b5ad750f1fe042a706a4e3d4_cgraph.svg" width="478" height="112"><p><b>This browser is not able to show SVG: try Firefox, Chrome, Safari, or Opera instead.</b></p></iframe>
</div>
</div>
</div>
</div>
<a id="abbbcebf3a2d0c67f4c3cfb5511a97981" name="abbbcebf3a2d0c67f4c3cfb5511a97981"></a>
<h2 class="memtitle"><span class="permalink"><a href="#abbbcebf3a2d0c67f4c3cfb5511a97981">&#9670;&nbsp;</a></span>test()</h2>
<div class="memitem">
<div class="memproto">
<table class="memname">
<tr>
<td class="memname">void test </td>
<td>(</td>
<td class="paramtype">uint64_t&#160;</td>
<td class="paramname"><em>n</em>, </td>
</tr>
<tr>
<td class="paramkey"></td>
<td></td>
<td class="paramtype">uint64_t&#160;</td>
<td class="paramname"><em>expected</em>&#160;</td>
</tr>
<tr>
<td></td>
<td>)</td>
<td></td><td></td>
</tr>
</table>
</div><div class="memdoc">
<p >Wrapper to run tests using both recursive and iterative implementations. The checks are only valid in debug builds due to the use of <code>assert()</code> statements. </p><dl class="params"><dt>Parameters</dt><dd>
<table class="params">
<tr><td class="paramdir">[in]</td><td class="paramname">n</td><td>number to check double factorial for </td></tr>
<tr><td class="paramdir">[in]</td><td class="paramname">expected</td><td>expected result </td></tr>
</table>
</dd>
</dl>
<div class="fragment"><div class="line"><a id="l00042" name="l00042"></a><span class="lineno"> 42</span> {</div>
<div class="line"><a id="l00043" name="l00043"></a><span class="lineno"> 43</span> assert(<a class="code hl_function" href="../../d7/d89/double__factorial_8cpp.html#a0a3c417360400093891a9ccddaa4be26">double_factorial_iterative</a>(n) == expected);</div>
<div class="line"><a id="l00044" name="l00044"></a><span class="lineno"> 44</span> assert(<a class="code hl_function" href="../../d7/d89/double__factorial_8cpp.html#a68ba20fed2ce427f6469c7689437829d">double_factorial_recursive</a>(n) == expected);</div>
<div class="line"><a id="l00045" name="l00045"></a><span class="lineno"> 45</span>}</div>
<div class="ttc" id="adouble__factorial_8cpp_html_a0a3c417360400093891a9ccddaa4be26"><div class="ttname"><a href="../../d7/d89/double__factorial_8cpp.html#a0a3c417360400093891a9ccddaa4be26">double_factorial_iterative</a></div><div class="ttdeci">uint64_t double_factorial_iterative(uint64_t n)</div><div class="ttdef"><b>Definition:</b> double_factorial.cpp:17</div></div>
</div><!-- fragment --><div class="dynheader">
Here is the call graph for this function:</div>
<div class="dyncontent">
<div class="center"><iframe scrolling="no" frameborder="0" src="../../d7/d89/double__factorial_8cpp_abbbcebf3a2d0c67f4c3cfb5511a97981_cgraph.svg" width="280" height="112"><p><b>This browser is not able to show SVG: try Firefox, Chrome, Safari, or Opera instead.</b></p></iframe>
</div>
</div>
</div>
</div>
<a id="a88ec9ad42717780d6caaff9d3d6977f9" name="a88ec9ad42717780d6caaff9d3d6977f9"></a>
<h2 class="memtitle"><span class="permalink"><a href="#a88ec9ad42717780d6caaff9d3d6977f9">&#9670;&nbsp;</a></span>tests()</h2>
<div class="memitem">
<div class="memproto">
<table class="memname">
<tr>
<td class="memname">void tests </td>
<td>(</td>
<td class="paramname"></td><td>)</td>
<td></td>
</tr>
</table>
</div><div class="memdoc">
<p >Test implementations </p>
<div class="fragment"><div class="line"><a id="l00050" name="l00050"></a><span class="lineno"> 50</span> {</div>
<div class="line"><a id="l00051" name="l00051"></a><span class="lineno"> 51</span> <a class="code hl_classRef" target="_blank" href="http://en.cppreference.com/w/cpp/io/basic_ostream.html">std::cout</a> &lt;&lt; <span class="stringliteral">&quot;Test 1:\t n=5\t...&quot;</span>;</div>
<div class="line"><a id="l00052" name="l00052"></a><span class="lineno"> 52</span> <a class="code hl_function" href="../../d7/d89/double__factorial_8cpp.html#abbbcebf3a2d0c67f4c3cfb5511a97981">test</a>(5, 15);</div>
<div class="line"><a id="l00053" name="l00053"></a><span class="lineno"> 53</span> <a class="code hl_classRef" target="_blank" href="http://en.cppreference.com/w/cpp/io/basic_ostream.html">std::cout</a> &lt;&lt; <span class="stringliteral">&quot;passed\n&quot;</span>;</div>
<div class="line"><a id="l00054" name="l00054"></a><span class="lineno"> 54</span> </div>
<div class="line"><a id="l00055" name="l00055"></a><span class="lineno"> 55</span> <a class="code hl_classRef" target="_blank" href="http://en.cppreference.com/w/cpp/io/basic_ostream.html">std::cout</a> &lt;&lt; <span class="stringliteral">&quot;Test 2:\t n=15\t...&quot;</span>;</div>
<div class="line"><a id="l00056" name="l00056"></a><span class="lineno"> 56</span> <a class="code hl_function" href="../../d7/d89/double__factorial_8cpp.html#abbbcebf3a2d0c67f4c3cfb5511a97981">test</a>(15, 2027025);</div>
<div class="line"><a id="l00057" name="l00057"></a><span class="lineno"> 57</span> <a class="code hl_classRef" target="_blank" href="http://en.cppreference.com/w/cpp/io/basic_ostream.html">std::cout</a> &lt;&lt; <span class="stringliteral">&quot;passed\n&quot;</span>;</div>
<div class="line"><a id="l00058" name="l00058"></a><span class="lineno"> 58</span> </div>
<div class="line"><a id="l00059" name="l00059"></a><span class="lineno"> 59</span> <a class="code hl_classRef" target="_blank" href="http://en.cppreference.com/w/cpp/io/basic_ostream.html">std::cout</a> &lt;&lt; <span class="stringliteral">&quot;Test 3:\t n=0\t...&quot;</span>;</div>
<div class="line"><a id="l00060" name="l00060"></a><span class="lineno"> 60</span> <a class="code hl_function" href="../../d7/d89/double__factorial_8cpp.html#abbbcebf3a2d0c67f4c3cfb5511a97981">test</a>(0, 1);</div>
<div class="line"><a id="l00061" name="l00061"></a><span class="lineno"> 61</span> <a class="code hl_classRef" target="_blank" href="http://en.cppreference.com/w/cpp/io/basic_ostream.html">std::cout</a> &lt;&lt; <span class="stringliteral">&quot;passed\n&quot;</span>;</div>
<div class="line"><a id="l00062" name="l00062"></a><span class="lineno"> 62</span>}</div>
<div class="ttc" id="abasic_ostream_html"><div class="ttname"><a href="http://en.cppreference.com/w/cpp/io/basic_ostream.html">std::cout</a></div></div>
<div class="ttc" id="adouble__factorial_8cpp_html_abbbcebf3a2d0c67f4c3cfb5511a97981"><div class="ttname"><a href="../../d7/d89/double__factorial_8cpp.html#abbbcebf3a2d0c67f4c3cfb5511a97981">test</a></div><div class="ttdeci">void test(uint64_t n, uint64_t expected)</div><div class="ttdef"><b>Definition:</b> double_factorial.cpp:42</div></div>
</div><!-- fragment --><div class="dynheader">
Here is the call graph for this function:</div>
<div class="dyncontent">
<div class="center"><iframe scrolling="no" frameborder="0" src="../../d7/d89/double__factorial_8cpp_a88ec9ad42717780d6caaff9d3d6977f9_cgraph.svg" width="379" height="112"><p><b>This browser is not able to show SVG: try Firefox, Chrome, Safari, or Opera instead.</b></p></iframe>
</div>
</div>
</div>
</div>
</div><!-- contents -->
</div><!-- doc-content -->
<!-- start footer part -->
<div id="nav-path" class="navpath"><!-- id is needed for treeview function! -->
<ul>
<li class="navelem"><a class="el" href="../../dir_296d53ceaeaa7e099814a6def439fe8a.html">math</a></li><li class="navelem"><a class="el" href="../../d7/d89/double__factorial_8cpp.html">double_factorial.cpp</a></li>
<li class="footer">Generated by <a href="https://www.doxygen.org/index.html"><img class="footer" src="../../doxygen.svg" width="104" height="31" alt="doxygen"/></a> 1.9.2 </li>
</ul>
</div>
</body>
</html>
Reference in New Issue View Git Blame Copy Permalink