函数声明:clock_t clock( void );
clock_t 是 long 型,typedef long clock_t;
clock() 使用的头文件是:time.h
CLOCK_PER_SEC表示每一秒经历的时钟数。通常我们用clock_t now = clock(); while(i--); finish = clock(); seconds = (finish - now)/CLOCK_PER_SEC; seconds表示进程持续的时间。
例如MSDN中一个clock()的例子:
#include"time.h"
#include"stdlib.h"
#include"stdio.h"
void sleep( clock_t wait );
void main( void )
{
long i = 600000L;
clock_t start, finish;
double duration;
printf( "Delay for three seconds\n" );
sleep( (clock_t)3 * CLOCKS_PER_SEC );
printf( "Done!\n" );
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 );
}
void sleep( clock_t wait )
{
clock_t goal;
goal = wait + clock();
while( goal > clock() )
;
}
Output