WebFeb 20, 2012 · CLOCKS_PER_SEC,它用来表示一秒钟会有多少个时钟计时单元,其定义如下: #define CLOCKS_PER_SEC ((clock_t)1000) 可以看到每过千分之一秒(1毫 … Web可以回答这个问题。计算1到n的和可以使用循环语句实现,累加法是将每个数依次相加,高斯法是将1到n的数分成两组,每组相加再相加得到总和。计算时间可以使用clock()函数来获取程序运行的时钟周期数,再除以CLOCKS_PER_SEC得到运行时间。
CLOCKS_PER_SEC - cppreference.com
Webclock_t clock (void); clock()函数返回一个数字,表示从程序开始到现在的 CPU 时钟周期的次数。这个值的类型是 clock_t,一般是 long int 类型。 为了把这个值转换为秒,应该把它除以常量CLOCKS_PER_SEC(每秒的时钟周期),这个常量也由time.h定义。 Webtypedef /* unspecified */ clock_t; 足以表示进程所用的处理器时间的 算术 (C11 前) 实数 (C11 起) 类型。 它拥有实现定义的范围和精度。 flag decals on trucks rules
Why is CLOCKS_PER_SEC not the actual number of clocks per second?
WebPOSIX.1-2001, POSIX.1-2008, C89, C99. XSI requires that CLOCKS_PER_SEC equals 1000000 independent of the actual resolution. NOTES top The C standard allows for arbitrary values at the start of the program; subtract the value returned from a call to clock() at the start of the program to get maximum portability. Note that the time can wrap around. WebCLOCKS_PER_SEC. Expands to an expression (not necessarily a compile-time constant) of type std::clock_t equal to the number of clock ticks per second, as returned by … We would like to show you a description here but the site won’t allow us. WebJul 23, 2024 · dispatch_time_t time = dispatch_time(DISPATCH_TIME_NOW, 3ull * NSEC_PER_SEC); 其中:ull 是C语言的数值字面量,是显式表明类型时使用的字符串( … flag decals for truck