CLOCKS_PER_SEC在C语言中找到了time.h库
CLOCKS_PER_SEC in C language found the time.h library
CLOCKS_PER_SEC 是否因系统而异,或者对于操作系统来说是不变的,还是取决于特定系统的处理器?
还要帮我解释我的代码输出...对吗??
#include<stdio.h>
#include<time.h>
int main()
{
int a;
long int b;
clock_t start, end;
start = clock();
//Code for which the time is to be calculated
for(a=0;;a++)
{
if(a<0)
{
break;
}
}
printf("int : %u\n",a);
for(b=0;;b++)
{
if(b<0)
{
break;
}
}
printf("long int :%u\n",b);
//code is over
end = clock();
//CLOCKS_PER_SECOND : the number of clock ticks per second
printf("Starting Time:%u\n",start);
printf("Ending Time:%u\n",end);
printf("CLOCKS_PER_SEC:%u",CLOCKS_PER_SEC);
printf("\nNumber of clock ticks:%u",(end - start));
printf("\nTotal time:%u",(double)(end - start)/CLOCKS_PER_SEC);
return 0;
}
输出:
int : 2147483648
long int :2147483648
Starting Time:0
Ending Time:9073
CLOCKS_PER_SEC:1000
Number of clock ticks:9073
Total time:1099511628
Process returned 0 (0x0) execution time : 15.653 s
Press any key to continue.
Does CLOCKS_PER_SEC varies from system to system or is it constant for an operating system or is it dependent on the processor of that particular system?
CLOCKS_PER_SEC
最终由编译器及其标准库实现决定,而不是OS。尽管机器、OS 和其他因素都会影响编译器提供的功能。
help me explain the output of my code...is it right?
没有。 printf("\nTotal time:%u",(double)(end - start)/CLOCKS_PER_SEC);
正在使用 "%u"
打印 double
。
CLOCKS_PER_SEC
不一定是 unsigned
。
clock_t
不一定是 int
。 Ref
使用错误的 printf()
说明符会导致输出信息不足。
提示:启用所有编译器警告。
转换为宽类型并使用匹配的打印说明符。
clock_t start
// printf("Starting Time:%u\n",start);
printf("Starting Time:%g\n", (double) start);
// printf("CLOCKS_PER_SEC:%u",CLOCKS_PER_SEC);
printf("CLOCKS_PER_SEC:%g\n", (double) CLOCKS_PER_SEC);
// printf("\nTotal time:%u",(double)(end - start)/CLOCKS_PER_SEC);
printf("Total time:%g\n",(double)(end - start)/CLOCKS_PER_SEC);
甚至考虑 long double
.
long double t = (long double)(end - start)/CLOCKS_PER_SEC;
printf("Total time:%Lg\n", t);
CLOCKS_PER_SEC 是否因系统而异,或者对于操作系统来说是不变的,还是取决于特定系统的处理器? 还要帮我解释我的代码输出...对吗??
#include<stdio.h>
#include<time.h>
int main()
{
int a;
long int b;
clock_t start, end;
start = clock();
//Code for which the time is to be calculated
for(a=0;;a++)
{
if(a<0)
{
break;
}
}
printf("int : %u\n",a);
for(b=0;;b++)
{
if(b<0)
{
break;
}
}
printf("long int :%u\n",b);
//code is over
end = clock();
//CLOCKS_PER_SECOND : the number of clock ticks per second
printf("Starting Time:%u\n",start);
printf("Ending Time:%u\n",end);
printf("CLOCKS_PER_SEC:%u",CLOCKS_PER_SEC);
printf("\nNumber of clock ticks:%u",(end - start));
printf("\nTotal time:%u",(double)(end - start)/CLOCKS_PER_SEC);
return 0;
}
输出:
int : 2147483648
long int :2147483648
Starting Time:0
Ending Time:9073
CLOCKS_PER_SEC:1000
Number of clock ticks:9073
Total time:1099511628
Process returned 0 (0x0) execution time : 15.653 s
Press any key to continue.
Does CLOCKS_PER_SEC varies from system to system or is it constant for an operating system or is it dependent on the processor of that particular system?
CLOCKS_PER_SEC
最终由编译器及其标准库实现决定,而不是OS。尽管机器、OS 和其他因素都会影响编译器提供的功能。
help me explain the output of my code...is it right?
没有。 printf("\nTotal time:%u",(double)(end - start)/CLOCKS_PER_SEC);
正在使用 "%u"
打印 double
。
CLOCKS_PER_SEC
不一定是 unsigned
。
clock_t
不一定是 int
。 Ref
使用错误的 printf()
说明符会导致输出信息不足。
提示:启用所有编译器警告。
转换为宽类型并使用匹配的打印说明符。
clock_t start
// printf("Starting Time:%u\n",start);
printf("Starting Time:%g\n", (double) start);
// printf("CLOCKS_PER_SEC:%u",CLOCKS_PER_SEC);
printf("CLOCKS_PER_SEC:%g\n", (double) CLOCKS_PER_SEC);
// printf("\nTotal time:%u",(double)(end - start)/CLOCKS_PER_SEC);
printf("Total time:%g\n",(double)(end - start)/CLOCKS_PER_SEC);
甚至考虑 long double
.
long double t = (long double)(end - start)/CLOCKS_PER_SEC;
printf("Total time:%Lg\n", t);