c:time.h:clock
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c:time.h:clock [2013/01/22 22:02] |
c:time.h:clock [2024/02/16 01:04] (current) |
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| + | {{keywords>wiki library source code example reference}} | ||
| + | ===== clock ===== | ||
| + | |||
| + | <code c> | ||
| + | clock_t clock(void); | ||
| + | </code> | ||
| + | |||
| + | |||
| + | === Description === | ||
| + | |||
| + | The clock() function returns the processor time since the program started, or -1 if that information is unavailable.\\ | ||
| + | To convert the return value to seconds, divide it by CLOCKS_PER_SEC. (Note: if your compiler is POSIX compliant, then CLOCKS_PER_SEC is always defined as 1000000.) | ||
| + | |||
| + | |||
| + | ===== clock c example ===== | ||
| + | <code c> | ||
| + | /* | ||
| + | * clock example code | ||
| + | * http://code-reference.com/c/time.h/clock | ||
| + | */ | ||
| + | #include <stdio.h> | ||
| + | #include <time.h> | ||
| + | |||
| + | int main (void) | ||
| + | { | ||
| + | int sec = 5; | ||
| + | clock_t end = clock() + sec * CLOCKS_PER_SEC; | ||
| + | |||
| + | while (clock() < end) | ||
| + | { | ||
| + | // do something | ||
| + | } | ||
| + | |||
| + | return 0; | ||
| + | } | ||
| + | |||
| + | </code> | ||
| + | |||
| + | or | ||
| + | |||
| + | <code c> | ||
| + | /* | ||
| + | * clock example code | ||
| + | * http://code-reference.com/c/time.h/clock | ||
| + | */ | ||
| + | #include <stdio.h> | ||
| + | #include <time.h> | ||
| + | int main( void ) | ||
| + | { | ||
| + | clock_t start = clock(); | ||
| + | clock_t finish; | ||
| + | int i; | ||
| + | |||
| + | for (i = 0; i < 9999; ++i) { | ||
| + | printf("%i\n", i); | ||
| + | } | ||
| + | |||
| + | finish = clock(); | ||
| + | |||
| + | printf("executed \"printf\" %i times\nCocks per Sec: %li\nStart: %li\nFinish: %li\n",i , CLOCKS_PER_SEC, start, finish); | ||
| + | return 0; | ||
| + | } | ||
| + | |||
| + | </code> | ||
| + | |||
| + | === output === | ||
| + | executed "printf" 9999 times | ||
| + | Cocks per Sec: 1000000 | ||
| + | Start: 0 | ||
| + | Finish: 20000 | ||
| + | |||
| + | |||
| + | ==== see also ==== | ||
| + | [[c:time.h:time|time()]] [[c:time.h:difftime|difftime()]] | ||
| + | |||
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