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66
67<h1><a class="anchor" id="timer">Using timers to measure execution time </a></h1><p>In this example we are using the Real_Timer class to measure the execution time of a simple program. The Real_Timer class is included in the itmisc library.</p>
68<div class="fragment"><pre class="fragment"><span class="preprocessor">#include &lt;itpp/itbase.h&gt;</span>
69
70<span class="keyword">using namespace </span>itpp;
71
72<span class="comment">//These lines are needed for use of cout and endl</span>
73<span class="keyword">using</span> std::cout;
74<span class="keyword">using</span> std::endl;
75
76<span class="keywordtype">int</span> main() {
77        <span class="comment">//Declare the scalars used:</span>
78        <span class="keywordtype">long</span> i, sum, N;
79
80        <span class="comment">//Declare tt as an instance of the timer class:</span>
81        Real_Timer tt;
82
83        <span class="comment">//Initiate the variables:</span>
84        N = 1000000;
85        sum = 0;
86
87        <span class="comment">//Start and reset the timer:</span>
88        tt.tic();
89
90        <span class="comment">//Do some processing</span>
91        <span class="keywordflow">for</span> ( i = 0; i &lt; N; i++ ) {
92                sum += i;
93        }
94
95        <span class="comment">// Print the elapsed time</span>
96        tt.toc_print();
97
98        <span class="comment">//Print the result of the processing:</span>
99        cout &lt;&lt; <span class="stringliteral">&quot;The sum of all integers from 0 to &quot;</span> &lt;&lt; N - 1 &lt;&lt; <span class="stringliteral">&quot; equals &quot;</span> &lt;&lt; sum &lt;&lt; endl;
100
101        <span class="comment">//Exit program:</span>
102        <span class="keywordflow">return</span> 0;
103
104}
105</pre></div><p>When you run this program, the output will look something like this:</p>
106<div class="fragment"><pre class="fragment">Elapsed time = 0.000797055 seconds
107The sum of all integers from 0 to 999999 equals 1783293664
108</pre></div> </div>
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