Running time of functions - c++

Question

I am wanting to print the running time of my functions. For some reason my timer always returns 0. Can anyone tell me why?
double RunningTime(clock_t time1, clock_t time2)
{
double t=time1 - time2;
double time = (t*1000)/CLOCKS_PER_SEC;
return time;
}
int main()
{
clock_t start_time = clock();
// some code.....
clock_t end_time = clock();
std::cout << "Time elapsed: " << double(RunningTime(end_time, start_time)) << " ms";
return 0;
}
I attempted to use gettimeofday and it still returned 0.
double get_time()
{
struct timeval t;
gettimeofday(&t, NULL);
double d = t.tv_sec + (double) t.tv_usec/100000;
return d;
}
int main()
{
double time_start = get_time();
//Some code......
double time_end = get_time();
std::cout << time_end - time_start;
return 0;
}
Also tried using chrono and it gave me all kinds of build errors:
error: #error This file requires compiler and library support for the
upcoming ISO C++ standard, C++0x. This support is currently
experimental, and must be enabled with the -std=c++0x or -std=gnu++0x
compiler options.
warning: 'auto' will change meaning in C++0x; please remove it
error: ISO C++ forbids declaration of 't1' with no type error:
'std::chrono' has not been declared
error: request for member 'count' in '(t2 - t1)', which is of
non-class type 'int'
int main()
{
auto t1 = std::chrono::high_resolution_clock::now();
//Some code......
auto t2 = std::chrono::high_resolution_clock::now();
std::cout << "Time elapsed: " << std::chrono::duration_cast<std::chrono::milliseconds>(t2-t1).count() << " milliseconds\n";
return 0;
}

Answer 1

A timer tick is approximately equal to 1/CLOCKS_PER_SEC second, which is a millisecond resolution. To see a real (non-zero) number, you should either invoke a very long-time function or use another library with a higher time resolution facility:
new c++11x library chrono (use MSVS 2012)
boost::chrono (unfortunately, the library refers to a lot of others)
POSIX function gettimeofday, which gives you a 1 microsecond time resolution

Answer 2

After lots of trial and error I went with gettimeofday. Here is my code that I finally got to work properly.
double get_time()
{
struct timeval t;
gettimeofday(&t, NULL);
double d = t.tv_sec + (double) t.tv_usec/1000000;
return d;
}
int main()
{
double time_start = get_time();
//Some code.........
double time_end = get_time();
std::cout << time_end - time_start;
return 0;
}

Answer 3

A solution I have been using lately uses C++11's lambda functionality to time any arbitrary function call or series of actions.
#include <ctime>
#include <iostream>
#include <functional>
void timeit(std::function<void()> func) {
std::clock_t start = std::clock();
func();
int ms = (std::clock() - start) / (double) (CLOCKS_PER_SEC / 1000);
std::cout << "Finished in " << ms << "ms" << std::endl;
}
int main() {
timeit([] {
for (int i = 0; i < 10; ++i) {
std::cout << "i = " << i << std::endl;
}
});
return 0;
}