blocks|key|1203106|text|clock()返回自程序启动以来的时钟滴答数。有一个相关的常量CLOCKS_PER_SEC，它告诉您一秒钟内发生了多少个时钟节拍。因此，您可以像这样测试任何操作：|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|1203107|clock_t+startTime+=+clock();
doSomeOperation();
clock_t+endTime+=+clock();
clock_t+clockTicksTaken+=+endTime+-+startTime;
double+timeInSeconds+=+clockTicksTaken+/+(double)+CLOCKS_PER_SEC;|code-block|syntax|javascript|1203108|entityMap^0|0|7|V|E|0|0^^$0|@$1|2|3|4|5|6|7|M|8|@$9|N|A|O|B|C]|$9|P|A|Q|B|C]]|D|@]|E|$]]|$1|F|3|G|5|H|7|R|8|@]|D|@]|E|$I|J]]|$1|K|3|-4|5|6|7|S|8|@]|D|@]|E|$]]]|L|$]]

<code>clock()</code> returns the number of clock ticks since your program started. There is a related constant, <code>CLOCKS_PER_SEC</code>, which tells you how many clock ticks occur in one second. Thus, you can test any operation like this:

<pre><code>clock_t startTime = clock();
doSomeOperation();
clock_t endTime = clock();
clock_t clockTicksTaken = endTime - startTime;
double timeInSeconds = clockTicksTaken / (double) CLOCKS_PER_SEC;
</code></pre>

blocks|key|1203129|text|#include+<iostream>
#include+<cstdio>
#include+<ctime>

int+main()+{
++++std::clock_t+start;
++++double+duration;

++++start+=+std::clock();

++++/*+Your+algorithm+here+*/

++++duration+=+(+std::clock()+-+start+)+/+(double)+CLOCKS_PER_SEC;

++++std::cout<<"printf:+"<<+duration+<<'\n';
}|type|code-block|depth|inlineStyleRanges|entityRanges|data|syntax|javascript|1203130|unstyled|entityMap^0|0^^$0|@$1|2|3|4|5|6|7|G|8|@]|9|@]|A|$B|C]]|$1|D|3|-4|5|E|7|H|8|@]|9|@]|A|$]]]|F|$]]

<pre><code>#include &lt;iostream&gt;
#include &lt;cstdio&gt;
#include &lt;ctime&gt;

int main() {
 std::clock_t start;
 double duration;

 start = std::clock();

 /* Your algorithm here */

 duration = ( std::clock() - start ) / (double) CLOCKS_PER_SEC;

 std::cout&lt;&lt;"printf: "&lt;&lt; duration &lt;&lt;'\n';
}
</code></pre>

blocks|key|1203137|text|#include+<iostream>
#include+<ctime>
#include+<cstdlib>+//_sleep()++---+just+a+function+that+waits+a+certain+amount+of+milliseconds

using+namespace+std;

int+main()
{

++++clock_t+cl;+++++//initializing+a+clock+type

++++cl+=+clock();+++//starting+time+of+clock

++++_sleep(5167);+++//insert+code+here

++++cl+=+clock()+-+cl;++//end+point+of+clock

++++_sleep(1000);+++//testing+to+see+if+it+actually+stops+at+the+end+point

++++cout+<<+cl/(double)CLOCKS_PER_SEC+<<+endl;++//prints+the+determined+ticks+per+second+(seconds+passed)


++++return+0;
}

//outputs+"5.17"|type|code-block|depth|inlineStyleRanges|entityRanges|data|syntax|javascript|1203138|unstyled|entityMap^0|0^^$0|@$1|2|3|4|5|6|7|G|8|@]|9|@]|A|$B|C]]|$1|D|3|-4|5|E|7|H|8|@]|9|@]|A|$]]]|F|$]]

<pre><code>#include &lt;iostream&gt;
#include &lt;ctime&gt;
#include &lt;cstdlib&gt; //_sleep() --- just a function that waits a certain amount of milliseconds

using namespace std;

int main()
{

 clock_t cl; //initializing a clock type

 cl = clock(); //starting time of clock

 _sleep(5167); //insert code here

 cl = clock() - cl; //end point of clock

 _sleep(1000); //testing to see if it actually stops at the end point

 cout &lt;&lt; cl/(double)CLOCKS_PER_SEC &lt;&lt; endl; //prints the determined ticks per second (seconds passed)


 return 0;
}

//outputs "5.17"
</code></pre>

blocks|key|988707|text|另一种解决方案是使用std::chrono，它是可移植的，并且具有更高的精度(从C%2B%2B11开始就可以使用)。|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|988708|下面是一个示例：|988709|#include+<iostream>
#include+<chrono>
typedef+std::chrono::high_resolution_clock+Clock;

int+main()
{
++++auto+t1+=+Clock::now();
++++auto+t2+=+Clock::now();
++++std::cout+<<+"Delta+t2-t1:+"+
++++++++++++++<<+std::chrono::duration_cast<std::chrono::nanoseconds>(t2+-+t1).count()
++++++++++++++<<+"+nanoseconds"+<<+std::endl;
}|code-block|syntax|javascript|988710|在ideone.com上运行它给了我：|988711|Delta+t2-t1:+282+nanoseconds|988712|entityMap^0|A|B|0|0|0|0|0^^$0|@$1|2|3|4|5|6|7|S|8|@$9|T|A|U|B|C]]|D|@]|E|$]]|$1|F|3|G|5|6|7|V|8|@]|D|@]|E|$]]|$1|H|3|I|5|J|7|W|8|@]|D|@]|E|$K|L]]|$1|M|3|N|5|6|7|X|8|@]|D|@]|E|$]]|$1|O|3|P|5|J|7|Y|8|@]|D|@]|E|$K|L]]|$1|Q|3|-4|5|6|7|Z|8|@]|D|@]|E|$]]]|R|$]]

An alternative solution, which is portable and with higher precision, available since C++11, is to use <code>std::chrono</code>.

Here is an example:

<pre><code>#include &lt;iostream&gt;
#include &lt;chrono&gt;
typedef std::chrono::high_resolution_clock Clock;

int main()
{
 auto t1 = Clock::now();
 auto t2 = Clock::now();
 std::cout &lt;&lt; "Delta t2-t1: " 
 &lt;&lt; std::chrono::duration_cast&lt;std::chrono::nanoseconds&gt;(t2 - t1).count()
 &lt;&lt; " nanoseconds" &lt;&lt; std::endl;
}
</code></pre>

Running this on ideone.com gave me:

<pre><code>Delta t2-t1: 282 nanoseconds
</code></pre>

blocks|key|988733|text|你可能会对计时器感兴趣，比如:h:m:s。毫秒|type|unstyled|depth|inlineStyleRanges|entityRanges|data|988734|Linux操作系统中的代码：|988735|#include+<iostream>
#include+<unistd.h>

using+namespace+std;
void+newline();+

int+main()+{

int+msec+=+0;
int+sec+=+0;
int+min+=+0;
int+hr+=+0;


//cout+<<+"Press+any+key+to+start:";
//char+start+=+_gtech();

for+(;;)
{
++++++++newline();
++++++++++++++++if(msec+==+1000)
++++++++++++++++{
++++++++++++++++++++++++%2B%2Bsec;
++++++++++++++++++++++++msec+=+0;
++++++++++++++++}
++++++++++++++++if(sec+==+60)
++++++++++++++++{
++++++++++++++++++++++++%2B%2Bmin;
++++++++++++++++++++++++sec+=+0;+
++++++++++++++++}
++++++++++++++++if(min+==+60)
++++++++++++++++{
++++++++++++++++++++++++%2B%2Bhr;
++++++++++++++++++++++++min+=+0;
++++++++++++++++}
++++++++cout+<<+hr+<<+"+:+"+<<+min+<<+"+:+"+<<+sec+<<+"+.+"+<<+msec+<<+endl;
++++++++%2B%2Bmsec;
++++++++usleep(100000);+

}

++++return+0;
}

void+newline()
{
++++++++cout+<<+"\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n";
}|code-block|syntax|javascript|988736|entityMap^0|0|0|0^^$0|@$1|2|3|4|5|6|7|K|8|@]|9|@]|A|$]]|$1|B|3|C|5|6|7|L|8|@]|9|@]|A|$]]|$1|D|3|E|5|F|7|M|8|@]|9|@]|A|$G|H]]|$1|I|3|-4|5|6|7|N|8|@]|9|@]|A|$]]]|J|$]]

Probably you might be interested in timer like this :
H : M : S . Msec.

the code in Linux OS:

<pre><code>#include &lt;iostream&gt;
#include &lt;unistd.h&gt;

using namespace std;
void newline(); 

int main() {

int msec = 0;
int sec = 0;
int min = 0;
int hr = 0;


//cout &lt;&lt; "Press any key to start:";
//char start = _gtech();

for (;;)
{
 newline();
 if(msec == 1000)
 {
 ++sec;
 msec = 0;
 }
 if(sec == 60)
 {
 ++min;
 sec = 0; 
 }
 if(min == 60)
 {
 ++hr;
 min = 0;
 }
 cout &lt;&lt; hr &lt;&lt; " : " &lt;&lt; min &lt;&lt; " : " &lt;&lt; sec &lt;&lt; " . " &lt;&lt; msec &lt;&lt; endl;
 ++msec;
 usleep(100000); 

}

 return 0;
}

void newline()
{
 cout &lt;&lt; "\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n";
}
</code></pre>

How do I call <code>clock()</code> in <code>C++</code>?

For example, I want to test how much time a linear search takes to find a given element in an array.

How to use clock() in C++

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如何在C++中调用clock()例如，我想测试线性搜索在数组中查找给定元素需要多长时间。

问如何在C++中使用clock()
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