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<div id="projectbrief">Set of algorithms implemented in C.</div>
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<div class="title">binary_search.c File Reference</div> </div>
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<p>Program to perform <a href="https://en.wikipedia.org/wiki/Binary_search_algorithm">binary search</a> of a target value in a given <em>sorted</em> array.
<a href="#details">More...</a></p>
<div class="textblock"><code>#include &lt;assert.h&gt;</code><br />
<code>#include &lt;stdio.h&gt;</code><br />
</div><div class="textblock"><div class="dynheader">
Include dependency graph for binary_search.c:</div>
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Functions</h2></td></tr>
<tr class="memitem:a40855c608ca64048d04cff6526f0a582"><td class="memItemLeft" align="right" valign="top">int&#160;</td><td class="memItemRight" valign="bottom"><a class="el" href="../../df/d3b/binary__search_8c.html#a40855c608ca64048d04cff6526f0a582">binarysearch1</a> (const int *arr, int l, int r, int x)</td></tr>
<tr class="memdesc:a40855c608ca64048d04cff6526f0a582"><td class="mdescLeft">&#160;</td><td class="mdescRight">Recursive implementation. <a href="../../df/d3b/binary__search_8c.html#a40855c608ca64048d04cff6526f0a582">More...</a><br /></td></tr>
<tr class="separator:a40855c608ca64048d04cff6526f0a582"><td class="memSeparator" colspan="2">&#160;</td></tr>
<tr class="memitem:a908fd6d2ad0bba33f63f8454888a0032"><td class="memItemLeft" align="right" valign="top">int&#160;</td><td class="memItemRight" valign="bottom"><a class="el" href="../../df/d3b/binary__search_8c.html#a908fd6d2ad0bba33f63f8454888a0032">binarysearch2</a> (const int *arr, int l, int r, int x)</td></tr>
<tr class="memdesc:a908fd6d2ad0bba33f63f8454888a0032"><td class="mdescLeft">&#160;</td><td class="mdescRight">Iterative implementation. <a href="../../df/d3b/binary__search_8c.html#a908fd6d2ad0bba33f63f8454888a0032">More...</a><br /></td></tr>
<tr class="separator:a908fd6d2ad0bba33f63f8454888a0032"><td class="memSeparator" colspan="2">&#160;</td></tr>
<tr class="memitem:ae1a3968e7947464bee7714f6d43b7002"><td class="memItemLeft" align="right" valign="top"><a id="ae1a3968e7947464bee7714f6d43b7002"></a>
void&#160;</td><td class="memItemRight" valign="bottom"><a class="el" href="../../df/d3b/binary__search_8c.html#ae1a3968e7947464bee7714f6d43b7002">test</a> ()</td></tr>
<tr class="memdesc:ae1a3968e7947464bee7714f6d43b7002"><td class="mdescLeft">&#160;</td><td class="mdescRight">Test implementations. <br /></td></tr>
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int&#160;</td><td class="memItemRight" valign="bottom"><a class="el" href="../../df/d3b/binary__search_8c.html#a840291bc02cba5474a4cb46a9b9566fe">main</a> (void)</td></tr>
<tr class="memdesc:a840291bc02cba5474a4cb46a9b9566fe"><td class="mdescLeft">&#160;</td><td class="mdescRight">Main function. <br /></td></tr>
<tr class="separator:a840291bc02cba5474a4cb46a9b9566fe"><td class="memSeparator" colspan="2">&#160;</td></tr>
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<a name="details" id="details"></a><h2 class="groupheader">Detailed Description</h2>
<div class="textblock"><p>Program to perform <a href="https://en.wikipedia.org/wiki/Binary_search_algorithm">binary search</a> of a target value in a given <em>sorted</em> array. </p>
<dl class="section author"><dt>Authors</dt><dd><a href="https://github.com/theycallmemac">James McDermott</a> - recursive algorithm </dd>
<dd>
<a href="https://github.com/kvedala">Krishna Vedala</a> - iterative algorithm </dd></dl>
</div><h2 class="groupheader">Function Documentation</h2>
<a id="a40855c608ca64048d04cff6526f0a582"></a>
<h2 class="memtitle"><span class="permalink"><a href="#a40855c608ca64048d04cff6526f0a582">&#9670;&nbsp;</a></span>binarysearch1()</h2>
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<td class="memname">int binarysearch1 </td>
<td>(</td>
<td class="paramtype">const int *&#160;</td>
<td class="paramname"><em>arr</em>, </td>
</tr>
<tr>
<td class="paramkey"></td>
<td></td>
<td class="paramtype">int&#160;</td>
<td class="paramname"><em>l</em>, </td>
</tr>
<tr>
<td class="paramkey"></td>
<td></td>
<td class="paramtype">int&#160;</td>
<td class="paramname"><em>r</em>, </td>
</tr>
<tr>
<td class="paramkey"></td>
<td></td>
<td class="paramtype">int&#160;</td>
<td class="paramname"><em>x</em>&#160;</td>
</tr>
<tr>
<td></td>
<td>)</td>
<td></td><td></td>
</tr>
</table>
</div><div class="memdoc">
<p>Recursive implementation. </p>
<dl class="params"><dt>Parameters</dt><dd>
<table class="params">
<tr><td class="paramdir">[in]</td><td class="paramname">arr</td><td>array to search </td></tr>
<tr><td class="paramdir"></td><td class="paramname">l</td><td>left index of search range </td></tr>
<tr><td class="paramdir"></td><td class="paramname">r</td><td>right index of search range </td></tr>
<tr><td class="paramdir"></td><td class="paramname">x</td><td>target value to search for </td></tr>
</table>
</dd>
</dl>
<dl class="section return"><dt>Returns</dt><dd>location of x assuming array arr[l..r] is present </dd>
<dd>
-1 otherwise </dd></dl>
<div class="fragment"><div class="line"><a name="l00022"></a><span class="lineno"> 22</span>&#160;{</div>
<div class="line"><a name="l00023"></a><span class="lineno"> 23</span>&#160; <span class="keywordflow">if</span> (r &gt;= l)</div>
<div class="line"><a name="l00024"></a><span class="lineno"> 24</span>&#160; {</div>
<div class="line"><a name="l00025"></a><span class="lineno"> 25</span>&#160; <span class="keywordtype">int</span> mid = l + (r - l) / 2;</div>
<div class="line"><a name="l00026"></a><span class="lineno"> 26</span>&#160; </div>
<div class="line"><a name="l00027"></a><span class="lineno"> 27</span>&#160; <span class="comment">// If element is present at middle</span></div>
<div class="line"><a name="l00028"></a><span class="lineno"> 28</span>&#160; <span class="keywordflow">if</span> (arr[mid] == x)</div>
<div class="line"><a name="l00029"></a><span class="lineno"> 29</span>&#160; <span class="keywordflow">return</span> mid;</div>
<div class="line"><a name="l00030"></a><span class="lineno"> 30</span>&#160; </div>
<div class="line"><a name="l00031"></a><span class="lineno"> 31</span>&#160; <span class="comment">// If element is smaller than middle</span></div>
<div class="line"><a name="l00032"></a><span class="lineno"> 32</span>&#160; <span class="keywordflow">if</span> (arr[mid] &gt; x)</div>
<div class="line"><a name="l00033"></a><span class="lineno"> 33</span>&#160; <span class="keywordflow">return</span> <a class="code" href="../../df/d3b/binary__search_8c.html#a40855c608ca64048d04cff6526f0a582">binarysearch1</a>(arr, l, mid - 1, x);</div>
<div class="line"><a name="l00034"></a><span class="lineno"> 34</span>&#160; </div>
<div class="line"><a name="l00035"></a><span class="lineno"> 35</span>&#160; <span class="comment">// Else element is in right subarray</span></div>
<div class="line"><a name="l00036"></a><span class="lineno"> 36</span>&#160; <span class="keywordflow">return</span> <a class="code" href="../../df/d3b/binary__search_8c.html#a40855c608ca64048d04cff6526f0a582">binarysearch1</a>(arr, mid + 1, r, x);</div>
<div class="line"><a name="l00037"></a><span class="lineno"> 37</span>&#160; }</div>
<div class="line"><a name="l00038"></a><span class="lineno"> 38</span>&#160; </div>
<div class="line"><a name="l00039"></a><span class="lineno"> 39</span>&#160; <span class="comment">// When element is not present in array</span></div>
<div class="line"><a name="l00040"></a><span class="lineno"> 40</span>&#160; <span class="keywordflow">return</span> -1;</div>
<div class="line"><a name="l00041"></a><span class="lineno"> 41</span>&#160;}</div>
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<h2 class="memtitle"><span class="permalink"><a href="#a908fd6d2ad0bba33f63f8454888a0032">&#9670;&nbsp;</a></span>binarysearch2()</h2>
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<td class="memname">int binarysearch2 </td>
<td>(</td>
<td class="paramtype">const int *&#160;</td>
<td class="paramname"><em>arr</em>, </td>
</tr>
<tr>
<td class="paramkey"></td>
<td></td>
<td class="paramtype">int&#160;</td>
<td class="paramname"><em>l</em>, </td>
</tr>
<tr>
<td class="paramkey"></td>
<td></td>
<td class="paramtype">int&#160;</td>
<td class="paramname"><em>r</em>, </td>
</tr>
<tr>
<td class="paramkey"></td>
<td></td>
<td class="paramtype">int&#160;</td>
<td class="paramname"><em>x</em>&#160;</td>
</tr>
<tr>
<td></td>
<td>)</td>
<td></td><td></td>
</tr>
</table>
</div><div class="memdoc">
<p>Iterative implementation. </p>
<dl class="params"><dt>Parameters</dt><dd>
<table class="params">
<tr><td class="paramdir">[in]</td><td class="paramname">arr</td><td>array to search </td></tr>
<tr><td class="paramdir"></td><td class="paramname">l</td><td>left index of search range </td></tr>
<tr><td class="paramdir"></td><td class="paramname">r</td><td>right index of search range </td></tr>
<tr><td class="paramdir"></td><td class="paramname">x</td><td>target value to search for </td></tr>
</table>
</dd>
</dl>
<dl class="section return"><dt>Returns</dt><dd>location of x assuming array arr[l..r] is present </dd>
<dd>
-1 otherwise </dd></dl>
<div class="fragment"><div class="line"><a name="l00052"></a><span class="lineno"> 52</span>&#160;{</div>
<div class="line"><a name="l00053"></a><span class="lineno"> 53</span>&#160; <span class="keywordtype">int</span> mid = l + (r - l) / 2;</div>
<div class="line"><a name="l00054"></a><span class="lineno"> 54</span>&#160; </div>
<div class="line"><a name="l00055"></a><span class="lineno"> 55</span>&#160; <span class="keywordflow">while</span> (arr[mid] != x)</div>
<div class="line"><a name="l00056"></a><span class="lineno"> 56</span>&#160; {</div>
<div class="line"><a name="l00057"></a><span class="lineno"> 57</span>&#160; <span class="keywordflow">if</span> (r &lt;= l || r &lt; 0)</div>
<div class="line"><a name="l00058"></a><span class="lineno"> 58</span>&#160; <span class="keywordflow">return</span> -1;</div>
<div class="line"><a name="l00059"></a><span class="lineno"> 59</span>&#160; </div>
<div class="line"><a name="l00060"></a><span class="lineno"> 60</span>&#160; <span class="keywordflow">if</span> (arr[mid] &gt; x)</div>
<div class="line"><a name="l00061"></a><span class="lineno"> 61</span>&#160; <span class="comment">// If element is smaller than middle</span></div>
<div class="line"><a name="l00062"></a><span class="lineno"> 62</span>&#160; r = mid - 1;</div>
<div class="line"><a name="l00063"></a><span class="lineno"> 63</span>&#160; <span class="keywordflow">else</span></div>
<div class="line"><a name="l00064"></a><span class="lineno"> 64</span>&#160; <span class="comment">// Else element is in right subarray</span></div>
<div class="line"><a name="l00065"></a><span class="lineno"> 65</span>&#160; l = mid + 1;</div>
<div class="line"><a name="l00066"></a><span class="lineno"> 66</span>&#160; </div>
<div class="line"><a name="l00067"></a><span class="lineno"> 67</span>&#160; mid = l + (r - l) / 2;</div>
<div class="line"><a name="l00068"></a><span class="lineno"> 68</span>&#160; }</div>
<div class="line"><a name="l00069"></a><span class="lineno"> 69</span>&#160; </div>
<div class="line"><a name="l00070"></a><span class="lineno"> 70</span>&#160; <span class="comment">// When element is not present in array</span></div>
<div class="line"><a name="l00071"></a><span class="lineno"> 71</span>&#160; <span class="keywordflow">return</span> mid;</div>
<div class="line"><a name="l00072"></a><span class="lineno"> 72</span>&#160;}</div>
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<div class="ttc" id="abinary__search_8c_html_a40855c608ca64048d04cff6526f0a582"><div class="ttname"><a href="../../df/d3b/binary__search_8c.html#a40855c608ca64048d04cff6526f0a582">binarysearch1</a></div><div class="ttdeci">int binarysearch1(const int *arr, int l, int r, int x)</div><div class="ttdoc">Recursive implementation.</div><div class="ttdef"><b>Definition:</b> binary_search.c:21</div></div>
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