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<div id="projectbrief">Set of algorithms implemented in C.</div>
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<a href="#func-members">Functions</a> &#124;
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<p><a href="https://projecteuler.net/problem=23" target="_blank">Problem 23</a> solution - optimization using look-up array
<a href="#details">More...</a></p>
<div class="textblock"><code>#include &lt;stdio.h&gt;</code><br />
<code>#include &lt;stdlib.h&gt;</code><br />
<code>#include &lt;time.h&gt;</code><br />
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Include dependency graph for sol2.c:</div>
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Functions</h2></td></tr>
<tr class="memitem:a1aca7f530f82b27100262adba9e7556b"><td class="memItemLeft" align="right" valign="top">char&#160;</td><td class="memItemRight" valign="bottom"><a class="el" href="../../d4/dbd/problem__23_2sol2_8c.html#a1aca7f530f82b27100262adba9e7556b">get_perfect_number</a> (unsigned long N)</td></tr>
<tr class="separator:a1aca7f530f82b27100262adba9e7556b"><td class="memSeparator" colspan="2">&#160;</td></tr>
<tr class="memitem:a34f4ad85151e3a43368ae67f42347f56"><td class="memItemLeft" align="right" valign="top">char&#160;</td><td class="memItemRight" valign="bottom"><a class="el" href="../../d4/dbd/problem__23_2sol2_8c.html#a34f4ad85151e3a43368ae67f42347f56">is_abundant</a> (unsigned long N)</td></tr>
<tr class="memdesc:a34f4ad85151e3a43368ae67f42347f56"><td class="mdescLeft">&#160;</td><td class="mdescRight">Is the given number an abundant number (1) or not (0) <a href="../../d4/dbd/problem__23_2sol2_8c.html#a34f4ad85151e3a43368ae67f42347f56">More...</a><br /></td></tr>
<tr class="separator:a34f4ad85151e3a43368ae67f42347f56"><td class="memSeparator" colspan="2">&#160;</td></tr>
<tr class="memitem:ac5d600bf3077f4188afc4c5cd2c40eaf"><td class="memItemLeft" align="right" valign="top">unsigned long&#160;</td><td class="memItemRight" valign="bottom"><a class="el" href="../../d4/dbd/problem__23_2sol2_8c.html#ac5d600bf3077f4188afc4c5cd2c40eaf">get_next_abundant</a> (unsigned long N)</td></tr>
<tr class="memdesc:ac5d600bf3077f4188afc4c5cd2c40eaf"><td class="mdescLeft">&#160;</td><td class="mdescRight">Find the next abundant number after N and not including N. <a href="../../d4/dbd/problem__23_2sol2_8c.html#ac5d600bf3077f4188afc4c5cd2c40eaf">More...</a><br /></td></tr>
<tr class="separator:ac5d600bf3077f4188afc4c5cd2c40eaf"><td class="memSeparator" colspan="2">&#160;</td></tr>
<tr class="memitem:a3ab61b5a1c4f2288625d160aa0ea8478"><td class="memItemLeft" align="right" valign="top">char&#160;</td><td class="memItemRight" valign="bottom"><a class="el" href="../../d4/dbd/problem__23_2sol2_8c.html#a3ab61b5a1c4f2288625d160aa0ea8478">is_sum_of_abundant</a> (unsigned long N)</td></tr>
<tr class="memdesc:a3ab61b5a1c4f2288625d160aa0ea8478"><td class="mdescLeft">&#160;</td><td class="mdescRight">check if a given number can be represented as a sum of two abundant numbers. <a href="../../d4/dbd/problem__23_2sol2_8c.html#a3ab61b5a1c4f2288625d160aa0ea8478">More...</a><br /></td></tr>
<tr class="separator:a3ab61b5a1c4f2288625d160aa0ea8478"><td class="memSeparator" colspan="2">&#160;</td></tr>
<tr class="memitem:a3c04138a5bfe5d72780bb7e82a18e627"><td class="memItemLeft" align="right" valign="top">int&#160;</td><td class="memItemRight" valign="bottom"><a class="el" href="../../d4/dbd/problem__23_2sol2_8c.html#a3c04138a5bfe5d72780bb7e82a18e627">main</a> (int argc, char **argv)</td></tr>
<tr class="memdesc:a3c04138a5bfe5d72780bb7e82a18e627"><td class="mdescLeft">&#160;</td><td class="mdescRight">Main function. <a href="../../d4/dbd/problem__23_2sol2_8c.html#a3c04138a5bfe5d72780bb7e82a18e627">More...</a><br /></td></tr>
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Variables</h2></td></tr>
<tr class="memitem:af920a16d6ef69dd604b283f427892e06"><td class="memItemLeft" align="right" valign="top">char *&#160;</td><td class="memItemRight" valign="bottom"><a class="el" href="../../d4/dbd/problem__23_2sol2_8c.html#af920a16d6ef69dd604b283f427892e06">abundant_flags</a> = NULL</td></tr>
<tr class="memdesc:af920a16d6ef69dd604b283f427892e06"><td class="mdescLeft">&#160;</td><td class="mdescRight">This is the global array to be used to store a flag to identify if a particular number is abundant (1) or not (0). <a href="../../d4/dbd/problem__23_2sol2_8c.html#af920a16d6ef69dd604b283f427892e06">More...</a><br /></td></tr>
<tr class="separator:af920a16d6ef69dd604b283f427892e06"><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 ><a href="https://projecteuler.net/problem=23" target="_blank">Problem 23</a> solution - optimization using look-up array </p>
<dl class="section author"><dt>Author</dt><dd><a href="https://github.com/kvedala" target="_blank">Krishna Vedala</a></dd></dl>
<p>Optimization applied - compute &amp; store abundant numbers once into a look-up array. </p>
</div><h2 class="groupheader">Function Documentation</h2>
<a id="ac5d600bf3077f4188afc4c5cd2c40eaf" name="ac5d600bf3077f4188afc4c5cd2c40eaf"></a>
<h2 class="memtitle"><span class="permalink"><a href="#ac5d600bf3077f4188afc4c5cd2c40eaf">&#9670;&#160;</a></span>get_next_abundant()</h2>
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<td class="memname">unsigned long get_next_abundant </td>
<td>(</td>
<td class="paramtype">unsigned long&#160;</td>
<td class="paramname"><em>N</em></td><td>)</td>
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<p>Find the next abundant number after N and not including N. </p>
<div class="fragment"><div class="line"><span class="lineno"> 71</span>{</div>
<div class="line"><span class="lineno"> 72</span> <span class="keywordtype">unsigned</span> <span class="keywordtype">long</span> i;</div>
<div class="line"><span class="lineno"> 73</span> <span class="comment">/* keep checking successive numbers till an abundant number is found */</span></div>
<div class="line"><span class="lineno"> 74</span> <span class="keywordflow">for</span> (i = N + 1; !<a class="code hl_function" href="../../d4/dbd/problem__23_2sol2_8c.html#a34f4ad85151e3a43368ae67f42347f56">is_abundant</a>(i); ++i)</div>
<div class="line"><span class="lineno"> 75</span> {</div>
<div class="line"><span class="lineno"> 76</span> ;</div>
<div class="line"><span class="lineno"> 77</span> }</div>
<div class="line"><span class="lineno"> 78</span> <span class="keywordflow">return</span> i;</div>
<div class="line"><span class="lineno"> 79</span>}</div>
<div class="ttc" id="aproblem__23_2sol2_8c_html_a34f4ad85151e3a43368ae67f42347f56"><div class="ttname"><a href="../../d4/dbd/problem__23_2sol2_8c.html#a34f4ad85151e3a43368ae67f42347f56">is_abundant</a></div><div class="ttdeci">char is_abundant(unsigned long N)</div><div class="ttdoc">Is the given number an abundant number (1) or not (0)</div><div class="ttdef"><b>Definition:</b> sol2.c:59</div></div>
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<h2 class="memtitle"><span class="permalink"><a href="#a1aca7f530f82b27100262adba9e7556b">&#9670;&#160;</a></span>get_perfect_number()</h2>
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<td class="memname">char get_perfect_number </td>
<td>(</td>
<td class="paramtype">unsigned long&#160;</td>
<td class="paramname"><em>N</em></td><td>)</td>
<td></td>
</tr>
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</div><div class="memdoc">
<dl class="section return"><dt>Returns</dt><dd>-1 if N is deficient </dd>
<dd>
1 if N is abundant </dd>
<dd>
0 if N is perfect </dd></dl>
<div class="fragment"><div class="line"><span class="lineno"> 32</span>{</div>
<div class="line"><span class="lineno"> 33</span> <span class="keywordtype">unsigned</span> <span class="keywordtype">long</span> sum = 1;</div>
<div class="line"><span class="lineno"> 34</span> <span class="keywordtype">char</span> ret = 0;</div>
<div class="line"><span class="lineno"> 35</span> </div>
<div class="line"><span class="lineno"> 36</span> <span class="keywordflow">for</span> (<span class="keywordtype">unsigned</span> <span class="keywordtype">long</span> i = 2; i * i &lt;= N; i++)</div>
<div class="line"><span class="lineno"> 37</span> {</div>
<div class="line"><span class="lineno"> 38</span> <span class="keywordflow">if</span> (N % i == 0)</div>
<div class="line"><span class="lineno"> 39</span> {</div>
<div class="line"><span class="lineno"> 40</span> sum += i;</div>
<div class="line"><span class="lineno"> 41</span> <span class="keywordtype">unsigned</span> <span class="keywordtype">long</span> tmp = N / i;</div>
<div class="line"><span class="lineno"> 42</span> <span class="keywordflow">if</span> (tmp != i)</div>
<div class="line"><span class="lineno"> 43</span> {</div>
<div class="line"><span class="lineno"> 44</span> sum += tmp;</div>
<div class="line"><span class="lineno"> 45</span> }</div>
<div class="line"><span class="lineno"> 46</span> }</div>
<div class="line"><span class="lineno"> 47</span> }</div>
<div class="line"><span class="lineno"> 48</span> </div>
<div class="line"><span class="lineno"> 49</span> ret = sum == N ? 0 : (sum &gt; N ? 1 : -1);</div>
<div class="line"><span class="lineno"> 50</span><span class="preprocessor">#ifdef DEBUG</span></div>
<div class="line"><span class="lineno"> 51</span> printf(<span class="stringliteral">&quot;%5lu: %5lu : %d\n&quot;</span>, N, sum, ret);</div>
<div class="line"><span class="lineno"> 52</span><span class="preprocessor">#endif</span></div>
<div class="line"><span class="lineno"> 53</span> <span class="keywordflow">return</span> ret;</div>
<div class="line"><span class="lineno"> 54</span>}</div>
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<h2 class="memtitle"><span class="permalink"><a href="#a34f4ad85151e3a43368ae67f42347f56">&#9670;&#160;</a></span>is_abundant()</h2>
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<td class="memname">char is_abundant </td>
<td>(</td>
<td class="paramtype">unsigned long&#160;</td>
<td class="paramname"><em>N</em></td><td>)</td>
<td></td>
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<p>Is the given number an abundant number (1) or not (0) </p>
<div class="fragment"><div class="line"><span class="lineno"> 60</span>{</div>
<div class="line"><span class="lineno"> 61</span> <span class="comment">// return abundant_flags[N &gt;&gt; 3] &amp; (1 &lt;&lt; N % 8) ? 1 : 0;</span></div>
<div class="line"><span class="lineno"> 62</span> <span class="keywordflow">return</span> <a class="code hl_variable" href="../../d4/dbd/problem__23_2sol2_8c.html#af920a16d6ef69dd604b283f427892e06">abundant_flags</a>[N &gt;&gt; 3] &amp; (1 &lt;&lt; (N &amp; 7))</div>
<div class="line"><span class="lineno"> 63</span> ? 1</div>
<div class="line"><span class="lineno"> 64</span> : 0; <span class="comment">/* optimized modulo operation */</span></div>
<div class="line"><span class="lineno"> 65</span>}</div>
<div class="ttc" id="aproblem__23_2sol2_8c_html_af920a16d6ef69dd604b283f427892e06"><div class="ttname"><a href="../../d4/dbd/problem__23_2sol2_8c.html#af920a16d6ef69dd604b283f427892e06">abundant_flags</a></div><div class="ttdeci">char * abundant_flags</div><div class="ttdoc">This is the global array to be used to store a flag to identify if a particular number is abundant (1...</div><div class="ttdef"><b>Definition:</b> sol2.c:24</div></div>
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<h2 class="memtitle"><span class="permalink"><a href="#a3ab61b5a1c4f2288625d160aa0ea8478">&#9670;&#160;</a></span>is_sum_of_abundant()</h2>
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<td class="memname">char is_sum_of_abundant </td>
<td>(</td>
<td class="paramtype">unsigned long&#160;</td>
<td class="paramname"><em>N</em></td><td>)</td>
<td></td>
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<p>check if a given number can be represented as a sum of two abundant numbers. </p>
<dl class="section return"><dt>Returns</dt><dd>1 - if yes </dd>
<dd>
0 - if not </dd></dl>
<div class="fragment"><div class="line"><span class="lineno"> 88</span>{</div>
<div class="line"><span class="lineno"> 89</span> <span class="comment">/* optimized logic:</span></div>
<div class="line"><span class="lineno"> 90</span><span class="comment"> * i + j = N where both i and j should be abundant</span></div>
<div class="line"><span class="lineno"> 91</span><span class="comment"> * hence we can simply check for j = N - i as we loop through i</span></div>
<div class="line"><span class="lineno"> 92</span><span class="comment"> */</span></div>
<div class="line"><span class="lineno"> 93</span> <span class="keywordflow">for</span> (<span class="keywordtype">unsigned</span> <span class="keywordtype">long</span> i = <a class="code hl_function" href="../../d4/dbd/problem__23_2sol2_8c.html#ac5d600bf3077f4188afc4c5cd2c40eaf">get_next_abundant</a>(1); i &lt;= (N &gt;&gt; 1);</div>
<div class="line"><span class="lineno"> 94</span> i = <a class="code hl_function" href="../../d4/dbd/problem__23_2sol2_8c.html#ac5d600bf3077f4188afc4c5cd2c40eaf">get_next_abundant</a>(i))</div>
<div class="line"><span class="lineno"> 95</span> {</div>
<div class="line"><span class="lineno"> 96</span> <span class="keywordflow">if</span> (<a class="code hl_function" href="../../d4/dbd/problem__23_2sol2_8c.html#a34f4ad85151e3a43368ae67f42347f56">is_abundant</a>(N - i))</div>
<div class="line"><span class="lineno"> 97</span> {</div>
<div class="line"><span class="lineno"> 98</span><span class="preprocessor">#ifdef DEBUG</span></div>
<div class="line"><span class="lineno"> 99</span> printf(<span class="stringliteral">&quot;\t%4lu + %4lu = %4lu\n&quot;</span>, i, N - i, N);</div>
<div class="line"><span class="lineno"> 100</span><span class="preprocessor">#endif</span></div>
<div class="line"><span class="lineno"> 101</span> <span class="keywordflow">return</span> 1;</div>
<div class="line"><span class="lineno"> 102</span> }</div>
<div class="line"><span class="lineno"> 103</span> }</div>
<div class="line"><span class="lineno"> 104</span> <span class="keywordflow">return</span> 0;</div>
<div class="line"><span class="lineno"> 105</span>}</div>
<div class="ttc" id="aproblem__23_2sol2_8c_html_ac5d600bf3077f4188afc4c5cd2c40eaf"><div class="ttname"><a href="../../d4/dbd/problem__23_2sol2_8c.html#ac5d600bf3077f4188afc4c5cd2c40eaf">get_next_abundant</a></div><div class="ttdeci">unsigned long get_next_abundant(unsigned long N)</div><div class="ttdoc">Find the next abundant number after N and not including N.</div><div class="ttdef"><b>Definition:</b> sol2.c:70</div></div>
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<h2 class="memtitle"><span class="permalink"><a href="#a3c04138a5bfe5d72780bb7e82a18e627">&#9670;&#160;</a></span>main()</h2>
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<td class="memname">int main </td>
<td>(</td>
<td class="paramtype">int&#160;</td>
<td class="paramname"><em>argc</em>, </td>
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<td class="paramkey"></td>
<td></td>
<td class="paramtype">char **&#160;</td>
<td class="paramname"><em>argv</em>&#160;</td>
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<td>)</td>
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<p>Main function. </p>
<div class="fragment"><div class="line"><span class="lineno"> 109</span>{</div>
<div class="line"><span class="lineno"> 110</span> <span class="keywordtype">long</span> MAX_N = 28123; <span class="comment">/* Limit of numbers to check */</span></div>
<div class="line"><span class="lineno"> 111</span> </div>
<div class="line"><span class="lineno"> 112</span> <span class="keywordtype">unsigned</span> <span class="keywordtype">long</span> sum = 0;</div>
<div class="line"><span class="lineno"> 113</span> <span class="keywordflow">if</span> (argc == 2)</div>
<div class="line"><span class="lineno"> 114</span> {</div>
<div class="line"><span class="lineno"> 115</span> MAX_N = strtoul(argv[1], NULL, 10);</div>
<div class="line"><span class="lineno"> 116</span> }</div>
<div class="line"><span class="lineno"> 117</span> </div>
<div class="line"><span class="lineno"> 118</span> <span class="comment">/* byte array to store flags to identify abundant numbers</span></div>
<div class="line"><span class="lineno"> 119</span><span class="comment"> * the flags are identified by bits</span></div>
<div class="line"><span class="lineno"> 120</span><span class="comment"> */</span></div>
<div class="line"><span class="lineno"> 121</span> <a class="code hl_variable" href="../../d4/dbd/problem__23_2sol2_8c.html#af920a16d6ef69dd604b283f427892e06">abundant_flags</a> = (<span class="keywordtype">char</span> *)<a class="code hl_define" href="../../d2/ddd/malloc__dbg_8h.html#afdddaa949a93c1ef559a638e98f9c21b">calloc</a>(MAX_N &gt;&gt; 3, 1);</div>
<div class="line"><span class="lineno"> 122</span> <span class="keywordflow">if</span> (!<a class="code hl_variable" href="../../d4/dbd/problem__23_2sol2_8c.html#af920a16d6ef69dd604b283f427892e06">abundant_flags</a>)</div>
<div class="line"><span class="lineno"> 123</span> {</div>
<div class="line"><span class="lineno"> 124</span> perror(<span class="stringliteral">&quot;Unable to allocate memoey!&quot;</span>);</div>
<div class="line"><span class="lineno"> 125</span> <span class="keywordflow">return</span> -1;</div>
<div class="line"><span class="lineno"> 126</span> }</div>
<div class="line"><span class="lineno"> 127</span> </div>
<div class="line"><span class="lineno"> 128</span><span class="preprocessor">#ifdef _OPENMP</span></div>
<div class="line"><span class="lineno"> 129</span> printf(<span class="stringliteral">&quot;Using OpenMP parallleization with %d threads\n&quot;</span>,</div>
<div class="line"><span class="lineno"> 130</span> omp_get_max_threads());</div>
<div class="line"><span class="lineno"> 131</span><span class="preprocessor">#else</span></div>
<div class="line"><span class="lineno"> 132</span> printf(<span class="stringliteral">&quot;Not using parallleization!\n&quot;</span>);</div>
<div class="line"><span class="lineno"> 133</span><span class="preprocessor">#endif</span></div>
<div class="line"><span class="lineno"> 134</span> </div>
<div class="line"><span class="lineno"> 135</span> clock_t start_time = clock();</div>
<div class="line"><span class="lineno"> 136</span> </div>
<div class="line"><span class="lineno"> 137</span> <span class="comment">/* Loop to set abundant flags */</span></div>
<div class="line"><span class="lineno"> 138</span> <span class="keywordtype">long</span> N;</div>
<div class="line"><span class="lineno"> 139</span><span class="preprocessor">#ifdef _OPENMP</span></div>
<div class="line"><span class="lineno"> 140</span><span class="preprocessor">#pragma omp for schedule(runtime)</span></div>
<div class="line"><span class="lineno"> 141</span><span class="preprocessor">#endif</span></div>
<div class="line"><span class="lineno"> 142</span> <span class="keywordflow">for</span> (N = 1; N &lt;= MAX_N; N++)</div>
<div class="line"><span class="lineno"> 143</span> {</div>
<div class="line"><span class="lineno"> 144</span> <span class="keywordtype">char</span> ret = <a class="code hl_function" href="../../d4/dbd/problem__23_2sol2_8c.html#a1aca7f530f82b27100262adba9e7556b">get_perfect_number</a>(N);</div>
<div class="line"><span class="lineno"> 145</span> <span class="keywordflow">if</span> (ret == 1)</div>
<div class="line"><span class="lineno"> 146</span> {</div>
<div class="line"><span class="lineno"> 147</span> <span class="comment">// int byte_offset = N % 8, index = N &gt;&gt; 3;</span></div>
<div class="line"><span class="lineno"> 148</span> <span class="keywordtype">int</span> byte_offset = N &amp; 7, index = N &gt;&gt; 3;</div>
<div class="line"><span class="lineno"> 149</span><span class="preprocessor">#ifdef _OPENMP</span></div>
<div class="line"><span class="lineno"> 150</span><span class="preprocessor">#pragma omp critical</span></div>
<div class="line"><span class="lineno"> 151</span><span class="preprocessor">#endif</span></div>
<div class="line"><span class="lineno"> 152</span> <a class="code hl_variable" href="../../d4/dbd/problem__23_2sol2_8c.html#af920a16d6ef69dd604b283f427892e06">abundant_flags</a>[index] |= ret &lt;&lt; byte_offset;</div>
<div class="line"><span class="lineno"> 153</span> }</div>
<div class="line"><span class="lineno"> 154</span> <span class="comment">// if (i % 100 == 0)</span></div>
<div class="line"><span class="lineno"> 155</span> <span class="comment">// printf(&quot;... %5lu: %8lu\r&quot;, i, sum);</span></div>
<div class="line"><span class="lineno"> 156</span> }</div>
<div class="line"><span class="lineno"> 157</span> </div>
<div class="line"><span class="lineno"> 158</span> clock_t end_time = clock();</div>
<div class="line"><span class="lineno"> 159</span> <span class="keywordtype">double</span> t1 = 1e3 * (end_time - start_time) / CLOCKS_PER_SEC;</div>
<div class="line"><span class="lineno"> 160</span> printf(<span class="stringliteral">&quot;Time taken to get abundant numbers: %.4g ms\n&quot;</span>, t1);</div>
<div class="line"><span class="lineno"> 161</span> </div>
<div class="line"><span class="lineno"> 162</span> clock_t t2 = 0;</div>
<div class="line"><span class="lineno"> 163</span> <span class="keywordtype">long</span> i;</div>
<div class="line"><span class="lineno"> 164</span><span class="preprocessor">#ifdef _OPENMP</span></div>
<div class="line"><span class="lineno"> 165</span><span class="preprocessor">#pragma omp parallel for schedule(runtime) reduction(+ : sum)</span></div>
<div class="line"><span class="lineno"> 166</span><span class="preprocessor">#endif</span></div>
<div class="line"><span class="lineno"> 167</span> <span class="keywordflow">for</span> (i = 1; i &lt; MAX_N; i++)</div>
<div class="line"><span class="lineno"> 168</span> {</div>
<div class="line"><span class="lineno"> 169</span> clock_t start_time1 = clock();</div>
<div class="line"><span class="lineno"> 170</span> <span class="keywordflow">if</span> (!<a class="code hl_function" href="../../d4/dbd/problem__23_2sol2_8c.html#a3ab61b5a1c4f2288625d160aa0ea8478">is_sum_of_abundant</a>(i))</div>
<div class="line"><span class="lineno"> 171</span> {</div>
<div class="line"><span class="lineno"> 172</span> <span class="comment">// #ifdef _OPENMP</span></div>
<div class="line"><span class="lineno"> 173</span> <span class="comment">// #pragma omp critical</span></div>
<div class="line"><span class="lineno"> 174</span> <span class="comment">// #endif</span></div>
<div class="line"><span class="lineno"> 175</span> sum += i;</div>
<div class="line"><span class="lineno"> 176</span> }</div>
<div class="line"><span class="lineno"> 177</span> clock_t end_time1 = clock();</div>
<div class="line"><span class="lineno"> 178</span><span class="preprocessor">#ifdef _OPENMP</span></div>
<div class="line"><span class="lineno"> 179</span><span class="preprocessor">#pragma omp critical</span></div>
<div class="line"><span class="lineno"> 180</span><span class="preprocessor">#endif</span></div>
<div class="line"><span class="lineno"> 181</span> t2 += end_time1 - start_time1;</div>
<div class="line"><span class="lineno"> 182</span> </div>
<div class="line"><span class="lineno"> 183</span> printf(<span class="stringliteral">&quot;... %5lu: %8lu\r&quot;</span>, i, sum);</div>
<div class="line"><span class="lineno"> 184</span> <span class="keywordflow">if</span> (i % 100 == 0)</div>
<div class="line"><span class="lineno"> 185</span> {</div>
<div class="line"><span class="lineno"> 186</span> fflush(stdout);</div>
<div class="line"><span class="lineno"> 187</span> }</div>
<div class="line"><span class="lineno"> 188</span> }</div>
<div class="line"><span class="lineno"> 189</span> </div>
<div class="line"><span class="lineno"> 190</span><span class="preprocessor">#ifdef DEBUG</span></div>
<div class="line"><span class="lineno"> 191</span> putchar(<span class="charliteral">&#39;\n&#39;</span>);</div>
<div class="line"><span class="lineno"> 192</span><span class="preprocessor">#endif</span></div>
<div class="line"><span class="lineno"> 193</span> <span class="keywordtype">double</span> t22 = 1e3 * t2 / CLOCKS_PER_SEC;</div>
<div class="line"><span class="lineno"> 194</span> printf(<span class="stringliteral">&quot;Time taken for final sum: %.4g ms\nTotal Time taken: %.4g ms\n&quot;</span>,</div>
<div class="line"><span class="lineno"> 195</span> t22, t1 + t22);</div>
<div class="line"><span class="lineno"> 196</span> printf(<span class="stringliteral">&quot;Memory used: %lu bytes\n&quot;</span>, MAX_N &gt;&gt; 3);</div>
<div class="line"><span class="lineno"> 197</span> printf(</div>
<div class="line"><span class="lineno"> 198</span> <span class="stringliteral">&quot;Sum of numbers that cannot be represented as sum of two abundant &quot;</span></div>
<div class="line"><span class="lineno"> 199</span> <span class="stringliteral">&quot;numbers : %lu\n&quot;</span>,</div>
<div class="line"><span class="lineno"> 200</span> sum);</div>
<div class="line"><span class="lineno"> 201</span> </div>
<div class="line"><span class="lineno"> 202</span> <a class="code hl_define" href="../../d2/ddd/malloc__dbg_8h.html#a9cc854374299a1dd933bf62029761768">free</a>(<a class="code hl_variable" href="../../d4/dbd/problem__23_2sol2_8c.html#af920a16d6ef69dd604b283f427892e06">abundant_flags</a>);</div>
<div class="line"><span class="lineno"> 203</span> </div>
<div class="line"><span class="lineno"> 204</span> <span class="keywordflow">return</span> 0;</div>
<div class="line"><span class="lineno"> 205</span>}</div>
<div class="ttc" id="amalloc__dbg_8h_html_a9cc854374299a1dd933bf62029761768"><div class="ttname"><a href="../../d2/ddd/malloc__dbg_8h.html#a9cc854374299a1dd933bf62029761768">free</a></div><div class="ttdeci">#define free(ptr)</div><div class="ttdoc">This macro replace the standard free function with free_dbg.</div><div class="ttdef"><b>Definition:</b> malloc_dbg.h:26</div></div>
<div class="ttc" id="amalloc__dbg_8h_html_afdddaa949a93c1ef559a638e98f9c21b"><div class="ttname"><a href="../../d2/ddd/malloc__dbg_8h.html#afdddaa949a93c1ef559a638e98f9c21b">calloc</a></div><div class="ttdeci">#define calloc(elemCount, elemSize)</div><div class="ttdoc">This macro replace the standard calloc function with calloc_dbg.</div><div class="ttdef"><b>Definition:</b> malloc_dbg.h:22</div></div>
<div class="ttc" id="aproblem__23_2sol2_8c_html_a1aca7f530f82b27100262adba9e7556b"><div class="ttname"><a href="../../d4/dbd/problem__23_2sol2_8c.html#a1aca7f530f82b27100262adba9e7556b">get_perfect_number</a></div><div class="ttdeci">char get_perfect_number(unsigned long N)</div><div class="ttdef"><b>Definition:</b> sol2.c:31</div></div>
<div class="ttc" id="aproblem__23_2sol2_8c_html_a3ab61b5a1c4f2288625d160aa0ea8478"><div class="ttname"><a href="../../d4/dbd/problem__23_2sol2_8c.html#a3ab61b5a1c4f2288625d160aa0ea8478">is_sum_of_abundant</a></div><div class="ttdeci">char is_sum_of_abundant(unsigned long N)</div><div class="ttdoc">check if a given number can be represented as a sum of two abundant numbers.</div><div class="ttdef"><b>Definition:</b> sol2.c:87</div></div>
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<h2 class="groupheader">Variable Documentation</h2>
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<h2 class="memtitle"><span class="permalink"><a href="#af920a16d6ef69dd604b283f427892e06">&#9670;&#160;</a></span>abundant_flags</h2>
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<td class="memname">char* abundant_flags = NULL</td>
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<p>This is the global array to be used to store a flag to identify if a particular number is abundant (1) or not (0). </p>
<p >Using a whole byte to store a binary info would be redundant. We will use each byte to represent 8 numbers by relying on bits. This saves memory required by 1/8 </p>
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