DSP

关于clock，为啥我用例程算的时间运行结果都是0

2019-07-13 19:44发布

站内文章 / DSP
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/* CLOCK.C: This example prompts for how long * the program is to run and then continuously * displays the elapsed time for that period. */ #include #include #include void sleep( clock_t wait ); void main( void ) {   long    i = 600000L;   clock_t start, finish;   double  duration;   /* Delay for a specified time. */   printf( "Delay for three seconds/n" );   sleep( (clock_t)3 * CLOCKS_PER_SEC );   printf( "Done!/n" );   /* Measure the duration of an event. */   printf( "Time to do %ld empty loops is ", i );   start = clock();   while( i-- )      ;   finish = clock();   duration = (double)(finish - start) / CLOCKS_PER_SEC;   printf( "%2.1f seconds/n", duration ); } /* Pauses for a specified number of milliseconds. */ void sleep( clock_t wait ) {   clock_t goal;   goal = wait + clock();   while( goal > clock() )      ; } //************************我自己的输出结果都是000.0000秒？？？？

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